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   141篇
  免费   24篇
农学   2篇
  15篇
综合类   8篇
农作物   2篇
畜牧兽医   129篇
园艺   1篇
植物保护   8篇
  2022年   1篇
  2021年   2篇
  2020年   4篇
  2019年   1篇
  2018年   10篇
  2017年   5篇
  2016年   7篇
  2015年   2篇
  2014年   6篇
  2013年   11篇
  2012年   1篇
  2011年   4篇
  2010年   6篇
  2009年   4篇
  2008年   4篇
  2007年   7篇
  2006年   6篇
  2005年   4篇
  2004年   4篇
  2003年   5篇
  2002年   7篇
  2001年   5篇
  2000年   4篇
  1999年   4篇
  1998年   8篇
  1997年   5篇
  1996年   4篇
  1995年   4篇
  1992年   2篇
  1990年   3篇
  1987年   1篇
  1985年   1篇
  1984年   1篇
  1981年   2篇
  1979年   1篇
  1974年   1篇
  1972年   1篇
  1969年   5篇
  1968年   4篇
  1967年   5篇
  1966年   3篇
排序方式: 共有165条查询结果,搜索用时 0 毫秒
161.
162.
163.
164.
An epidemiological investigation of a calf rearing premises and a closely associated dairy herd was carried out after the isolation of Salmonella enterica serovar Paratyphi B variant Java phage type 3b variant 2 from clinically diseased calves on the premises. The isolate was resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, tetracyclines, trimethoprim and cefoperazone. The organism was widespread on the calf unit and was also recovered from the dairy premises, mainly from groups of weaned calves. The investigation was extended to 10 epidemiologically linked farms but no S Java was isolated from any of the 40 to 60 samples collected from each premises. Molecular studies showed that the S Java isolates were genetically most similar to isolates from cases of human disease associated with ornamental fish tanks or feed. Long PCR and resistance gene profiling identified a resistance island which was indistinguishable from the human 'fish tank' strain of S Java and animal and human epidemic strains of S Typhimurium DT104. The isolates were clearly distinguished from multi-resistant S Java strains commonly associated with continental poultry. This is the first report of S Java with this resistance pattern in Great Britain.  相似文献   
165.
In sub‐Saharan Africa, urban and peri‐urban food production has been identified as an important resource for meeting the challenges of rapidly growing cities, and the positive aspects of such production have been well documented in the literature. This paper examines some of the health and environmental concerns associated with urban and peri‐urban agriculture (UPA). Empirical evidence from the city of Kano in northern Nigeria suggests that there is currently much reason for concern as industrial and domestic toxins are reaching dangerously high levels. As soils and water channels become increasingly polluted, the sustainability of urban and peri‐urban food production is questioned. Since the health implications of long‐term exposure to toxins are unclear, it is suggested that coordinated longitudinal research involving urban planners, agricultural scientists and health specialists is urgently needed. In addition, it remains crucial that government and institutional actors effectively monitor and enforce both environmental and zoning by‐laws, if the health and environmental constraints of UPA are to be overcome, and the future sustainability of production is to be assured. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
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