乌克兰荷斯坦牛的区域繁育中心

IF 1.9 3区 农林科学 Q2 AGRICULTURE, DAIRY & ANIMAL SCIENCE
A. Pochukalin
{"title":"乌克兰荷斯坦牛的区域繁育中心","authors":"A. Pochukalin","doi":"10.31073/abg.65.11","DOIUrl":null,"url":null,"abstract":"Introduction. The prevalence of the Holstein breed in the natural and climatic zones allows for the analysis and assessment of the manifestation of breeding traits of milk productivity, exterior and reproductive ability of animals in farms of different forms of ownership. This makes it possible to establish the level of the main population genetic parameters and to carry out local measures to improve the selection work in subjects of the breeding business. Monitoring of the genealogical structure of the breed, identification of the most common lines, related groups, and their evaluation according to the main economically useful features is also carried out. \nThe purpose and tasks of this study was to establish the number and nature of the manifestation of selection traits of animals in the regions that breed breeding Holstein cattle of Ukraine. \nMaterials and methods of research. For the analysis of regional Holstein cattle breeding centers in Ukraine, materials from the comprehensive evaluation of breeding cattle as of 01.01.2021 were used in the amount of 5 farms in the Volyn region, 7 in the Dnipropetrovsk region, Kyiv region, Chernihiv region, 2 in Mykolaiv region, 12 in the Poltava region, and 9 in the Cherkasy region. To realize the goal, we used and conducted an analysis of the number of breeding cattle, the distribution of animals by milk yield, fat and protein content, calving, milk yield and live weight for the last completed I, II and III lactation, the characteristics of firstborns by the shape of the udder and the intensity of milk yield, reproduction ability and characteristics of record-breaking cows. The genealogical affiliation to the lines of the mother stock and breeding bulls, which were involved in reproduction, was determined using the information database of the bulls of Ukraine under the \"Orsek\" Dairy Management System. The average values of selection traits are calculated as a weighted average according to the generally accepted methodology. \nResearch results. The total number of researched livestock is 43679 heads, including 22823 cows, 18907 heifers, and 949 bulls of various age groups. By breed, 95% of the animals are purebred, and by class, 76% belong to the elite-record and elite. The share of sex-age groups in different regions is not the same and varies within the following limits: cows from 47% to 62.4%, heifers 6–12 months. from 14.9% to 21.2%, heifers 13–18 months from 7.4% to 17.7% and heifers older than 18 months. from 9.6% to 14.2%. The number of bulls aged 6–18 months. distributed in the Dnipropetrovsk, Kyiv and Chernihiv regions with a share from 2.9% to 5.6%. \nThe analysis of the distribution of cows in breeding farms showed that 14% of herds have up to 100 cows, 32% from 100 to 299 cows, 18% from 300 to 699 cows, 10% from 700 to 899 cows, and 8% from more than 1000 cows. \nThe share of firstborns, cows with the second, third calving and above compared to the total number of studied types is 40%–25%–35% = 23731 heads. In the regions, this ratio is, respectively: Volyn – 34%–23%–43% = 1678 heads, Dnipropetrovsk – 50–20–30% = 2475 heads, Kyiv – 40–30–30% = 6616 heads, Mykolaiv – 37–23–40% = 2549 heads, Poltava – 46–30–24% = 3981 heads, Cherkasy – 36–22–42% = 3070 heads, Chernihiv – 37–27–36% = 3362 heads. The studied regions are quite variable in terms of the main breeding trait, namely the milk productivity of cows. Thus, the average number of cows in the three regions exceeds 10 tons. \nThe lowest value was recorded in cows of the Dnipropetrovsk region. In addition, interesting from the point of view of the variability of the value of breeding in herds within the region is its amplitude. Thus, in Volyn it ranges from 7651 kg to 12112 kg, in Dnipropetrovsk from 4471 kg to 8753 kg, in Kyiv from 12320 kg to 8305 kg, in Mykolaiv from 8714 kg to 11355 kg, in Poltava from 6870 kg to 9553 kg, in Cherkasy from 551 kg to 11200 kg and Chernihiv from 7545 kg to 9630 kg. High values were noted for the content of fat in milk, where cows from five regions have a value above 3.80%, with the best indicator for cows from the Kyiv region. The lowest live weight of cows is 553 kg in the Dnipropetrovsk region, which is 11.8 kg less than the Poltava region and 40.8 kg less than the Cherkasy region. Cows of the Volyn, Kyiv, Mykolaiv and Chernihiv regions have a live weight of over 600 kg. \nIndicators of the reproductive ability of the mother stock of seven regions of Ukraine are variable according to the average values. Thus, heifers from the Dnipropetrovsk region have the lowest live weight for the 1-st insemination, which is 58.1 kg less than animals from the Mykolaiv region. The duration of the service period of cows in all regions is greater than the optimal values, which is explained by the high level of milk productivity. In the vast majority of cows in the studied regions, it is easy, and the proportion of heavy ones is within 3% ... 9%. \nThe main reasons for the abandonment of cows are low milk productivity and reproductive ability, with the exception of cows of the Dnipropetrovsk region, which ranges from 42% in the Mykolaiv region to 63.5% in the Cherkasy region. The share of diseases of the udder, limbs, and digestive organs has a wide amplitude and is, respectively, 4.6 ... 16.3%, 9.5 ... 23.9%, 1 ... 17.5%. The average age at which cows are removed from the studied herds ranges from 1 up to 3.5 calvings in Dnipropetrovsk, from 2.6 to 3 calvings in Kyiv, from 2.5 to 2.9 calvings in Mykolaivsk, from 2 to 5 calvings in Poltava, from 2 to 3.5 calvings in Cherkasy and from 2 up to 4 calvings in cows in the Chernihiv region. \nThe genealogical structure of the Holstein breed in the studied regions consists of 15 lines, the breeding bulls of which come from 18 countries. The largest number, namely 13 lines, is used in the Kyiv region, and the least in the Mykolaiv (7) regions. As for the prevalence of lines, in all regions the breeding bulls Bella 667366, Besna 5694028588, Valiant 1650414, Eleveishn 1491007, Marshal 2290977, Starbak 352790 and Chif 1427381 are used to 100% in Mykolaiv regions. The most used breeding bulls are from the Eleveishn 1491007, Starbak 352790 and Chif 1427381 lines, which respectively have the largest mother stock. \nConclusions. The smallest representation of the mother stock, as well as the bulls used on it, are Ivanhoe 1189870, Astronaut 1428744, Rigel 352882, Metta 132858, Montfrech 91779 and Cadillac 2046246 lines. According to milk yield, the cows of the studied bulls of the respective lines are characterized by wide differentiation, the best values of which exceed 10 t. In addition, in all regions, except Mykolaiv, there is a group of breeding stock with bulls whose lineage is not defined, and their share in the overall structure is, respectively: 2% in Kyiv, 7% in Dnipropetrovsk, 10% in Chernihiv, 20% in Cherkasy, 25% in Volyn. The USA, Canada, the Netherlands and Germany are among the largest importers of breeding bulls.","PeriodicalId":54885,"journal":{"name":"Journal of Animal Breeding and Genetics","volume":null,"pages":null},"PeriodicalIF":1.9000,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"REGIONAL CENTERS FOR THE BREEDING OF HOLSTEIN CATTLE OF UKRAINE\",\"authors\":\"A. Pochukalin\",\"doi\":\"10.31073/abg.65.11\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Introduction. The prevalence of the Holstein breed in the natural and climatic zones allows for the analysis and assessment of the manifestation of breeding traits of milk productivity, exterior and reproductive ability of animals in farms of different forms of ownership. This makes it possible to establish the level of the main population genetic parameters and to carry out local measures to improve the selection work in subjects of the breeding business. Monitoring of the genealogical structure of the breed, identification of the most common lines, related groups, and their evaluation according to the main economically useful features is also carried out. \\nThe purpose and tasks of this study was to establish the number and nature of the manifestation of selection traits of animals in the regions that breed breeding Holstein cattle of Ukraine. \\nMaterials and methods of research. For the analysis of regional Holstein cattle breeding centers in Ukraine, materials from the comprehensive evaluation of breeding cattle as of 01.01.2021 were used in the amount of 5 farms in the Volyn region, 7 in the Dnipropetrovsk region, Kyiv region, Chernihiv region, 2 in Mykolaiv region, 12 in the Poltava region, and 9 in the Cherkasy region. To realize the goal, we used and conducted an analysis of the number of breeding cattle, the distribution of animals by milk yield, fat and protein content, calving, milk yield and live weight for the last completed I, II and III lactation, the characteristics of firstborns by the shape of the udder and the intensity of milk yield, reproduction ability and characteristics of record-breaking cows. The genealogical affiliation to the lines of the mother stock and breeding bulls, which were involved in reproduction, was determined using the information database of the bulls of Ukraine under the \\\"Orsek\\\" Dairy Management System. The average values of selection traits are calculated as a weighted average according to the generally accepted methodology. \\nResearch results. The total number of researched livestock is 43679 heads, including 22823 cows, 18907 heifers, and 949 bulls of various age groups. By breed, 95% of the animals are purebred, and by class, 76% belong to the elite-record and elite. The share of sex-age groups in different regions is not the same and varies within the following limits: cows from 47% to 62.4%, heifers 6–12 months. from 14.9% to 21.2%, heifers 13–18 months from 7.4% to 17.7% and heifers older than 18 months. from 9.6% to 14.2%. The number of bulls aged 6–18 months. distributed in the Dnipropetrovsk, Kyiv and Chernihiv regions with a share from 2.9% to 5.6%. \\nThe analysis of the distribution of cows in breeding farms showed that 14% of herds have up to 100 cows, 32% from 100 to 299 cows, 18% from 300 to 699 cows, 10% from 700 to 899 cows, and 8% from more than 1000 cows. \\nThe share of firstborns, cows with the second, third calving and above compared to the total number of studied types is 40%–25%–35% = 23731 heads. In the regions, this ratio is, respectively: Volyn – 34%–23%–43% = 1678 heads, Dnipropetrovsk – 50–20–30% = 2475 heads, Kyiv – 40–30–30% = 6616 heads, Mykolaiv – 37–23–40% = 2549 heads, Poltava – 46–30–24% = 3981 heads, Cherkasy – 36–22–42% = 3070 heads, Chernihiv – 37–27–36% = 3362 heads. The studied regions are quite variable in terms of the main breeding trait, namely the milk productivity of cows. Thus, the average number of cows in the three regions exceeds 10 tons. \\nThe lowest value was recorded in cows of the Dnipropetrovsk region. In addition, interesting from the point of view of the variability of the value of breeding in herds within the region is its amplitude. Thus, in Volyn it ranges from 7651 kg to 12112 kg, in Dnipropetrovsk from 4471 kg to 8753 kg, in Kyiv from 12320 kg to 8305 kg, in Mykolaiv from 8714 kg to 11355 kg, in Poltava from 6870 kg to 9553 kg, in Cherkasy from 551 kg to 11200 kg and Chernihiv from 7545 kg to 9630 kg. High values were noted for the content of fat in milk, where cows from five regions have a value above 3.80%, with the best indicator for cows from the Kyiv region. The lowest live weight of cows is 553 kg in the Dnipropetrovsk region, which is 11.8 kg less than the Poltava region and 40.8 kg less than the Cherkasy region. Cows of the Volyn, Kyiv, Mykolaiv and Chernihiv regions have a live weight of over 600 kg. \\nIndicators of the reproductive ability of the mother stock of seven regions of Ukraine are variable according to the average values. Thus, heifers from the Dnipropetrovsk region have the lowest live weight for the 1-st insemination, which is 58.1 kg less than animals from the Mykolaiv region. The duration of the service period of cows in all regions is greater than the optimal values, which is explained by the high level of milk productivity. In the vast majority of cows in the studied regions, it is easy, and the proportion of heavy ones is within 3% ... 9%. \\nThe main reasons for the abandonment of cows are low milk productivity and reproductive ability, with the exception of cows of the Dnipropetrovsk region, which ranges from 42% in the Mykolaiv region to 63.5% in the Cherkasy region. The share of diseases of the udder, limbs, and digestive organs has a wide amplitude and is, respectively, 4.6 ... 16.3%, 9.5 ... 23.9%, 1 ... 17.5%. The average age at which cows are removed from the studied herds ranges from 1 up to 3.5 calvings in Dnipropetrovsk, from 2.6 to 3 calvings in Kyiv, from 2.5 to 2.9 calvings in Mykolaivsk, from 2 to 5 calvings in Poltava, from 2 to 3.5 calvings in Cherkasy and from 2 up to 4 calvings in cows in the Chernihiv region. \\nThe genealogical structure of the Holstein breed in the studied regions consists of 15 lines, the breeding bulls of which come from 18 countries. The largest number, namely 13 lines, is used in the Kyiv region, and the least in the Mykolaiv (7) regions. As for the prevalence of lines, in all regions the breeding bulls Bella 667366, Besna 5694028588, Valiant 1650414, Eleveishn 1491007, Marshal 2290977, Starbak 352790 and Chif 1427381 are used to 100% in Mykolaiv regions. The most used breeding bulls are from the Eleveishn 1491007, Starbak 352790 and Chif 1427381 lines, which respectively have the largest mother stock. \\nConclusions. The smallest representation of the mother stock, as well as the bulls used on it, are Ivanhoe 1189870, Astronaut 1428744, Rigel 352882, Metta 132858, Montfrech 91779 and Cadillac 2046246 lines. According to milk yield, the cows of the studied bulls of the respective lines are characterized by wide differentiation, the best values of which exceed 10 t. In addition, in all regions, except Mykolaiv, there is a group of breeding stock with bulls whose lineage is not defined, and their share in the overall structure is, respectively: 2% in Kyiv, 7% in Dnipropetrovsk, 10% in Chernihiv, 20% in Cherkasy, 25% in Volyn. The USA, Canada, the Netherlands and Germany are among the largest importers of breeding bulls.\",\"PeriodicalId\":54885,\"journal\":{\"name\":\"Journal of Animal Breeding and Genetics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2023-07-03\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Animal Breeding and Genetics\",\"FirstCategoryId\":\"97\",\"ListUrlMain\":\"https://doi.org/10.31073/abg.65.11\",\"RegionNum\":3,\"RegionCategory\":\"农林科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"AGRICULTURE, DAIRY & ANIMAL SCIENCE\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Animal Breeding and Genetics","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.31073/abg.65.11","RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"AGRICULTURE, DAIRY & ANIMAL SCIENCE","Score":null,"Total":0}
引用次数: 0

摘要

奶牛被遗弃的主要原因是产奶量和繁殖能力低,但第聂伯罗彼得罗夫斯克地区的奶牛除外,其比例从Mykolaiv地区的42%到切尔卡西地区的63.5%不等。乳房、四肢和消化器官疾病所占比例较大,分别为4.6。16.3%, 9.5…23.9%, 1…17.5%。从所研究的牛群中移除奶牛的平均年龄为第聂伯罗彼得罗夫斯克的1至3.5个小牛,基辅的2.6至3个小牛,米科莱夫斯克的2.5至2.9个小牛,波尔塔瓦的2至5个小牛,切尔卡西的2至3.5个小牛,切尔尼耶夫地区的2至4个小牛。研究地区荷斯坦种牛的谱系结构由15个系组成,种牛来自18个国家。最大的数字,即13行,用于基辅地区,最少的是在Mykolaiv地区(7)。在所有地区,贝拉667366、别斯纳5694028588、Valiant 1650414、elevishn 1491007、Marshal 2290977、Starbak 352790和Chif 1427381的种牛在Mykolaiv地区的使用率为100%。使用最多的种牛系分别是11ishn 1491007、Starbak 352790和Chif 1427381,它们分别拥有最大的母种。结论。母股的最小代表,以及上面使用的公牛,是艾芬豪1189870,宇航员1428744,Rigel 352882, Metta 132858, Montfrech 91779和凯迪拉克2046246线。根据产奶量,所研究的奶牛的各自品系的奶牛具有广泛分化的特点,其最佳值超过10 t。此外,在所有地区,除了尼古拉耶夫,都有一群公牛的血统没有确定,其在整体结构中的份额分别为:基辅2%,第聂伯罗彼得罗夫斯克7%,切尔尼耶夫10%,切尔卡西20%,沃林25%。美国、加拿大、荷兰和德国是最大的种牛进口国。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
REGIONAL CENTERS FOR THE BREEDING OF HOLSTEIN CATTLE OF UKRAINE
Introduction. The prevalence of the Holstein breed in the natural and climatic zones allows for the analysis and assessment of the manifestation of breeding traits of milk productivity, exterior and reproductive ability of animals in farms of different forms of ownership. This makes it possible to establish the level of the main population genetic parameters and to carry out local measures to improve the selection work in subjects of the breeding business. Monitoring of the genealogical structure of the breed, identification of the most common lines, related groups, and their evaluation according to the main economically useful features is also carried out. The purpose and tasks of this study was to establish the number and nature of the manifestation of selection traits of animals in the regions that breed breeding Holstein cattle of Ukraine. Materials and methods of research. For the analysis of regional Holstein cattle breeding centers in Ukraine, materials from the comprehensive evaluation of breeding cattle as of 01.01.2021 were used in the amount of 5 farms in the Volyn region, 7 in the Dnipropetrovsk region, Kyiv region, Chernihiv region, 2 in Mykolaiv region, 12 in the Poltava region, and 9 in the Cherkasy region. To realize the goal, we used and conducted an analysis of the number of breeding cattle, the distribution of animals by milk yield, fat and protein content, calving, milk yield and live weight for the last completed I, II and III lactation, the characteristics of firstborns by the shape of the udder and the intensity of milk yield, reproduction ability and characteristics of record-breaking cows. The genealogical affiliation to the lines of the mother stock and breeding bulls, which were involved in reproduction, was determined using the information database of the bulls of Ukraine under the "Orsek" Dairy Management System. The average values of selection traits are calculated as a weighted average according to the generally accepted methodology. Research results. The total number of researched livestock is 43679 heads, including 22823 cows, 18907 heifers, and 949 bulls of various age groups. By breed, 95% of the animals are purebred, and by class, 76% belong to the elite-record and elite. The share of sex-age groups in different regions is not the same and varies within the following limits: cows from 47% to 62.4%, heifers 6–12 months. from 14.9% to 21.2%, heifers 13–18 months from 7.4% to 17.7% and heifers older than 18 months. from 9.6% to 14.2%. The number of bulls aged 6–18 months. distributed in the Dnipropetrovsk, Kyiv and Chernihiv regions with a share from 2.9% to 5.6%. The analysis of the distribution of cows in breeding farms showed that 14% of herds have up to 100 cows, 32% from 100 to 299 cows, 18% from 300 to 699 cows, 10% from 700 to 899 cows, and 8% from more than 1000 cows. The share of firstborns, cows with the second, third calving and above compared to the total number of studied types is 40%–25%–35% = 23731 heads. In the regions, this ratio is, respectively: Volyn – 34%–23%–43% = 1678 heads, Dnipropetrovsk – 50–20–30% = 2475 heads, Kyiv – 40–30–30% = 6616 heads, Mykolaiv – 37–23–40% = 2549 heads, Poltava – 46–30–24% = 3981 heads, Cherkasy – 36–22–42% = 3070 heads, Chernihiv – 37–27–36% = 3362 heads. The studied regions are quite variable in terms of the main breeding trait, namely the milk productivity of cows. Thus, the average number of cows in the three regions exceeds 10 tons. The lowest value was recorded in cows of the Dnipropetrovsk region. In addition, interesting from the point of view of the variability of the value of breeding in herds within the region is its amplitude. Thus, in Volyn it ranges from 7651 kg to 12112 kg, in Dnipropetrovsk from 4471 kg to 8753 kg, in Kyiv from 12320 kg to 8305 kg, in Mykolaiv from 8714 kg to 11355 kg, in Poltava from 6870 kg to 9553 kg, in Cherkasy from 551 kg to 11200 kg and Chernihiv from 7545 kg to 9630 kg. High values were noted for the content of fat in milk, where cows from five regions have a value above 3.80%, with the best indicator for cows from the Kyiv region. The lowest live weight of cows is 553 kg in the Dnipropetrovsk region, which is 11.8 kg less than the Poltava region and 40.8 kg less than the Cherkasy region. Cows of the Volyn, Kyiv, Mykolaiv and Chernihiv regions have a live weight of over 600 kg. Indicators of the reproductive ability of the mother stock of seven regions of Ukraine are variable according to the average values. Thus, heifers from the Dnipropetrovsk region have the lowest live weight for the 1-st insemination, which is 58.1 kg less than animals from the Mykolaiv region. The duration of the service period of cows in all regions is greater than the optimal values, which is explained by the high level of milk productivity. In the vast majority of cows in the studied regions, it is easy, and the proportion of heavy ones is within 3% ... 9%. The main reasons for the abandonment of cows are low milk productivity and reproductive ability, with the exception of cows of the Dnipropetrovsk region, which ranges from 42% in the Mykolaiv region to 63.5% in the Cherkasy region. The share of diseases of the udder, limbs, and digestive organs has a wide amplitude and is, respectively, 4.6 ... 16.3%, 9.5 ... 23.9%, 1 ... 17.5%. The average age at which cows are removed from the studied herds ranges from 1 up to 3.5 calvings in Dnipropetrovsk, from 2.6 to 3 calvings in Kyiv, from 2.5 to 2.9 calvings in Mykolaivsk, from 2 to 5 calvings in Poltava, from 2 to 3.5 calvings in Cherkasy and from 2 up to 4 calvings in cows in the Chernihiv region. The genealogical structure of the Holstein breed in the studied regions consists of 15 lines, the breeding bulls of which come from 18 countries. The largest number, namely 13 lines, is used in the Kyiv region, and the least in the Mykolaiv (7) regions. As for the prevalence of lines, in all regions the breeding bulls Bella 667366, Besna 5694028588, Valiant 1650414, Eleveishn 1491007, Marshal 2290977, Starbak 352790 and Chif 1427381 are used to 100% in Mykolaiv regions. The most used breeding bulls are from the Eleveishn 1491007, Starbak 352790 and Chif 1427381 lines, which respectively have the largest mother stock. Conclusions. The smallest representation of the mother stock, as well as the bulls used on it, are Ivanhoe 1189870, Astronaut 1428744, Rigel 352882, Metta 132858, Montfrech 91779 and Cadillac 2046246 lines. According to milk yield, the cows of the studied bulls of the respective lines are characterized by wide differentiation, the best values of which exceed 10 t. In addition, in all regions, except Mykolaiv, there is a group of breeding stock with bulls whose lineage is not defined, and their share in the overall structure is, respectively: 2% in Kyiv, 7% in Dnipropetrovsk, 10% in Chernihiv, 20% in Cherkasy, 25% in Volyn. The USA, Canada, the Netherlands and Germany are among the largest importers of breeding bulls.
求助全文
通过发布文献求助,成功后即可免费获取论文全文。 去求助
来源期刊
Journal of Animal Breeding and Genetics
Journal of Animal Breeding and Genetics 农林科学-奶制品与动物科学
CiteScore
5.20
自引率
3.80%
发文量
58
审稿时长
12-24 weeks
期刊介绍: The Journal of Animal Breeding and Genetics publishes original articles by international scientists on genomic selection, and any other topic related to breeding programmes, selection, quantitative genetic, genomics, diversity and evolution of domestic animals. Researchers, teachers, and the animal breeding industry will find the reports of interest. Book reviews appear in many issues.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信