首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   82篇
  免费   9篇
林业   1篇
  1篇
综合类   13篇
水产渔业   6篇
畜牧兽医   66篇
植物保护   4篇
  2023年   2篇
  2022年   1篇
  2021年   5篇
  2020年   6篇
  2019年   2篇
  2018年   3篇
  2017年   3篇
  2016年   2篇
  2015年   3篇
  2014年   1篇
  2013年   16篇
  2012年   2篇
  2011年   3篇
  2010年   5篇
  2009年   5篇
  2008年   2篇
  2007年   4篇
  2006年   1篇
  2005年   2篇
  2004年   1篇
  2003年   1篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1998年   2篇
  1996年   1篇
  1993年   1篇
  1987年   1篇
  1983年   1篇
  1982年   3篇
  1979年   1篇
  1976年   1篇
  1963年   1篇
  1955年   1篇
  1943年   1篇
  1936年   1篇
  1930年   2篇
  1922年   1篇
排序方式: 共有91条查询结果,搜索用时 93 毫秒
1.
2.
At the time of AI following Ovsynch protocol, a total of 51 buffaloes were randomly divided in a first group (n = 30) subjected to conventional AI into the uterine body with 20 million non-sex sorted frozen-thawed spermatozoa, while a second group (n = 21) was inseminated near the utero-tubal junction (UTJ) ipsilateral to the ovary carrying the preovulatory follicle with 2.5 million live (4 million total) sex-sorted frozen-thawed spermatozoa. The semen used for flowcytometric sorting was collected and processed on a farm in Italy, and then shipped to a laboratory in Germany. Eleven buffaloes were inseminated with X-chromosome bearing spermatozoa and 10 with Y-chromosome bearing spermatozoa. Conception rates after conventional and UTJ inseminations were 43.3% (n = 13) and 42.8% (n = 9) respectively (p = 0.97). Eight of the nine foetuses obtained after insemination with sexed spermatozoa corresponded to the sex as predicted by the cell sorting procedure (five male and four female foetuses by ultrasound vs six male and three female foetuses by cell sorting). In conclusion, for the first time buffalo semen has been successfully subjected to procedures for flowcytometric sperm sorting and freezing. Low doses of sexed spermatozoa have been deposited near the UTJ giving conception rates similar to those of conventional AI with full dose.  相似文献   
3.
4.
5.
Foot and mouth disease (FMD) is a highly transmissible viral infection of cloven hooved animals associated with severe economic losses when introduced into FMD-free countries. Information on the impact of the disease in FMDV-endemic countries is poorly characterised yet essential for the prioritisation of scarce resources for disease control programmes. A FMD (virus serotype SAT2) outbreak on a large-scale dairy farm in Nakuru County, Kenya provided an opportunity to evaluate the impact of FMD on clinical mastitis and culling rate. A cohort approach followed animals over a 12-month period after the commencement of the outbreak. For culling, all animals were included; for mastitis, those over 18 months of age. FMD was recorded in 400/644 cattle over a 29-day period. During the follow-up period 76 animals were culled or died whilst in the over 18 month old cohort 63 developed clinical mastitis. Hazard ratios (HR) were generated using Cox regression accounting for non-proportional hazards by inclusion of time-varying effects. Univariable analysis showed FMD cases were culled sooner but there was no effect on clinical mastitis. After adjusting for possible confounders and inclusion of time-varying effects there was weak evidence to support an effect of FMD on culling (HR = 1.7, 95% confidence intervals [CI] 0.88-3.1, P = 0.12). For mastitis, there was stronger evidence of an increased rate in the first month after the onset of the outbreak (HR = 2.9, 95%CI 0.97-8.9, P = 0.057).

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0173-4) contains supplementary material, which is available to authorized users.  相似文献   
6.
Lignins and suberins are complex plant cell-wall macromolecules that are composed mainly of phenylpropanoid residues derived from L-phenylalanine. Lignins and suberins are considered to be covalently linked to carbohydrates and to lipids, respectively. The bonding of these important structural materials within cell walls has never been established. By feeding specifically labeled [(13)C] ferulic acid over extended durations to seedlings of Triticum aestivum L. and by using solid-state carbon-13 nuclear magnetic resonance techniques, the major resonances due to specific carbons in the propanoid side chains of these cell-wall polymers have been identified in situ. The signals were found to differ significantly from those of synthetic lignins, which have usually been considered to be good approximations of natural lignin structure.  相似文献   
7.
An experiment was performed with 36 growing pigs of Danish Landrace, to study the influence of digestible crude protein on the energy excretion with the urine and on the efficiency of utilization of metabolizable energy.The pigs (3 litters of females and 3 litters of male castrates) were distributed on six dietary treatments on a within-litter basis, taking into account the live weight of the pigs. The daily intake of the different diets was adjusted in such a way that the daily gain in the different treatment groups was almost identical through the entire experimental period from 20–90 kg.Three digestibility and nitrogen balance experiments were performed with each pig. At approximately 90 kg live weight the pigs were killed, dissected, ground, mixed and chemically analysed. The energy loss in urine increased by 4.9 kJ and the efficiency of utilization of metabolizable energy was decreased by approximately 6.6 kJ/g of catabolized protein.Digestibility experiments with ileo-caecal cannulated pigs indicated that the proportion of the digested energy disappearing in the caecum-colon increased with increasing dietary concentration of crude protein.  相似文献   
8.
9.
Highly conserved protective epitopes on influenza B viruses   总被引:1,自引:0,他引:1  
Identification of broadly neutralizing antibodies against influenza A viruses has raised hopes for the development of monoclonal antibody-based immunotherapy and "universal" vaccines for influenza. However, a substantial part of the annual flu burden is caused by two cocirculating, antigenically distinct lineages of influenza B viruses. Here, we report human monoclonal antibodies, CR8033, CR8071, and CR9114, that protect mice against lethal challenge from both lineages. Antibodies CR8033 and CR8071 recognize distinct conserved epitopes in the head region of the influenza B hemagglutinin (HA), whereas CR9114 binds a conserved epitope in the HA stem and protects against lethal challenge with influenza A and B viruses. These antibodies may inform on development of monoclonal antibody-based treatments and a universal flu vaccine for all influenza A and B viruses.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号