全文获取类型
收费全文 | 539篇 |
免费 | 47篇 |
国内免费 | 1篇 |
专业分类
林业 | 31篇 |
农学 | 26篇 |
基础科学 | 2篇 |
81篇 | |
综合类 | 26篇 |
农作物 | 30篇 |
水产渔业 | 70篇 |
畜牧兽医 | 235篇 |
园艺 | 11篇 |
植物保护 | 75篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 21篇 |
2021年 | 40篇 |
2020年 | 36篇 |
2019年 | 40篇 |
2018年 | 22篇 |
2017年 | 29篇 |
2016年 | 30篇 |
2015年 | 22篇 |
2014年 | 27篇 |
2013年 | 24篇 |
2012年 | 47篇 |
2011年 | 48篇 |
2010年 | 18篇 |
2009年 | 30篇 |
2008年 | 23篇 |
2007年 | 24篇 |
2006年 | 16篇 |
2005年 | 19篇 |
2004年 | 10篇 |
2003年 | 14篇 |
2002年 | 17篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有587条查询结果,搜索用时 0 毫秒
61.
Dilemma of virulence of Streptococcus suis: Canadian isolate 89-1591 characterized as a virulent strain using a standardized experimental model in pigs 总被引:4,自引:0,他引:4 下载免费PDF全文
Florence Berthelot-Hérault Marcelo Gottschalk Hervé Morvan Marylène Kobisch 《Canadian journal of veterinary research》2005,69(3):236-240
Virulence of Streptococccus suis capsular type 2 strain 89-1591 has been controversial in literature. A standardized experimental model with specific-pathogen free piglets was used for a new evaluation of this strain. Twenty-nine piglets were allotted in 4 separated groups. Group 1 consisted of negative control animals which received broth medium. Groups 2, 3, and 4 were intravenously challenged with 2 mL of S. suis, strains 1330, 89-1591, and 166', respectively. The strain 1330 is a recognized avirulent Canadian strain. The strain 166' is a reference French virulent isolate. Pigs inoculated with strain 1330 did not present clinical signs of a S. suis infection. Contamination in organs and bacterial blood circulation were rare and lesions were almost non-existent. Infection of pigs with S. suis strain 89-1591 (group 3) and 166' (group 4) caused severe clinical problems, animals infected with S. suis 166' were the most affected. Pigs presented with clinical signs such as high body temperature, lameness, nervous symptoms, and even mortality. Lesions associated with S. suis were numerous for both strains, but more evident in animals of group 4. It can be concluded that S. suis strain 89-1591 is virulent, although its virulence seems to be lower than that of the French strain. Results of an experimental infection with strain 89-1591 may depend on different factors such as the route of inoculation and the immunological status of the animals used. Using conventional animals, with an unknown status regarding previous S. suis infections, equivocal results may be obtained, and this may explain differences reported by some authors with the same strain. 相似文献
62.
63.
Phosphorus use efficiency (PUE) evaluation based on shoot dry weight in the early stages of plant development can be a useful measure to identify genotypes that are superior in phosphorus (P) use. The objectives of this study were to (i) identify inbred lines that are efficient and inefficient in P use, (ii) assess the genetic diversity among the inbred lines based on traits related to PUE, (iii) investigate the relationship among traits related to PUE and its components and (iv) estimate the expected responses to selection for increasing PUE. Twenty‐three S6 popcorn inbred lines were evaluated under high and low P, and several traits related to PUE and its components were measured. Efficient and inefficient inbred lines under each P level were identified, and the genetic diversity assessment grouped these inbred lines in opposite clusters. Phosphorus acquisition efficiency (PAE) was the most important component of PUE in the early stages of plant development, and the direct selection for PAE seems to be the best method for increasing PUE in these stages. 相似文献
64.
65.
Georgea Bignardi Jarretta Pedro Primo Bombonato Marcelo Alcindo de Barros Vaz Guimar?es 《Journal of zoo and wildlife medicine》2004,35(3):356-360
Ultrasonography is currently used in veterinary medicine to examine the anatomy and physiology of internal organs and to establish normal standards for exotic animal species. Specifically, the kidneys may be evaluated and measured in length, width, and height. The kidneys in 33 oncilla (Leopardus tigrinus), including 20 males and 13 females, were opportunistically located, characterized, and measured by ultrasound using a 7.5-MHz linear transducer at two different zoologic facilities in S?o Paulo, Brazil. Renal volume was calculated from these linear measurements. The mean linear measurements and volume of the right and left kidneys were not significantly different. 相似文献
66.
67.
68.
69.