全文获取类型
收费全文 | 97篇 |
免费 | 17篇 |
专业分类
林业 | 1篇 |
1篇 | |
综合类 | 10篇 |
水产渔业 | 2篇 |
畜牧兽医 | 98篇 |
园艺 | 1篇 |
植物保护 | 1篇 |
出版年
2023年 | 5篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
排序方式: 共有114条查询结果,搜索用时 15 毫秒
111.
112.
In a cross-sectional study of 6240 Danish Holstein cows in 55 herds using loose-housing systems, sole haemorrhages and heel horn erosions occurred frequently in almost all the herds. Digital dermatitis occurred in 47 of the 55 herds (85 per cent). Spearman correlation coefficients revealed relationships between lameness and sole ulcer (0.36), between heel horn erosion and sole haemorrhage (0.39), between heel horn erosion and interdigital dermatitis (0.29) and between sole ulcer and double sole (0.26). The prevalence of heel horn erosion, sole haemorrhage, interdigital dermatitis and digital dermatitis appeared to be most affected by herd-level factors. The associations between individual foot trimmers and all the foot lesions were statistically significant. The risk of interdigital dermatitis increased with decreasing amounts of bedding. Cows housed throughout the year had a marginally higher risk of sole haemorrhage. 相似文献
113.
114.
Nielsen MK Kaplan RM Thamsborg SM Monrad J Olsen SN 《Veterinary journal (London, England : 1997)》2007,174(1):23-32
Development of resistance to anthelmintic drugs by horse strongyles constitutes a growing threat to equine health because it is unknown when new drug classes can be expected on the market. Consequently, parasite control strategies should attempt to maintain drug efficacy for as long as possible. The proportion of a parasite population that is not exposed to anthelmintic treatment is described as being "in refugia" and although many factors affect the rate at which resistance develops, levels of refugia are considered the most important as these parasites are not selected by treatment and so provide a pool of sensitive genes in the population. Accordingly, treatment should be avoided when pasture refugia are small because such treatments will place significant selection pressure for resistance on worm populations. Given this new paradigm for parasite control, it has become important to identify seasons and circumstances wherein refugia are diminished. Free-living stages of equine strongyles are highly dependent on climatic influences, and this review summarises studies of strongyle development and survival under laboratory and field conditions in Northern (cool) temperate, Southern (warm) temperate and subtropical/tropical climates. In Northern temperate climates, refugia are smallest during the winter. In contrast, refugia are lowest during the summer in warm temperate and subtropical/tropical climates. Although adverse seasonal changes clearly have significant effects on the ability of free living stages of strongyle nematode parasites to survive and develop, available data suggest that climatic influences cannot effectively "clean" pastures from one grazing season to the next. 相似文献