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   200篇
  免费   4篇
  国内免费   1篇
林业   9篇
农学   15篇
  19篇
综合类   37篇
农作物   6篇
水产渔业   3篇
畜牧兽医   106篇
园艺   4篇
植物保护   6篇
  2023年   4篇
  2022年   8篇
  2021年   10篇
  2020年   7篇
  2019年   7篇
  2018年   8篇
  2017年   5篇
  2016年   1篇
  2015年   2篇
  2014年   10篇
  2013年   10篇
  2012年   6篇
  2011年   15篇
  2010年   8篇
  2009年   7篇
  2008年   3篇
  2007年   4篇
  2006年   6篇
  2005年   7篇
  2004年   5篇
  2003年   7篇
  2002年   7篇
  2001年   1篇
  2000年   1篇
  1999年   4篇
  1998年   6篇
  1997年   11篇
  1996年   9篇
  1995年   3篇
  1994年   1篇
  1993年   3篇
  1992年   3篇
  1991年   4篇
  1990年   2篇
  1989年   6篇
  1988年   1篇
  1985年   1篇
  1982年   1篇
  1981年   1篇
排序方式: 共有205条查询结果,搜索用时 156 毫秒
101.
用自选及从省内外引进的13个自交系(其中有5个自交系具有贵州地方血缘),按Griffing完全双列杂交方法四组配78个杂交组合,进行了田间试验。估算了这些自交系产量性状的一般配合力效应。结果表明,自交系大013﹑交51、5003的一般配合力较高。  相似文献   
102.
103.
Animal welfare is expected to increase in importance as a political and marketing issue. There is a vigorous debate about what, besides the absence of physical pain, is necessary for acceptable animal welfare. This paper focuses on the present state of animal welfare policy at the national level.  相似文献   
104.
Tree species and external signs of decay influence the felling criteria in risk assessments. Following felling in Helsinki, Finland, 133 urban trees were investigated in detail (54 trees of Tilia spp., 48 Betula spp., and 31 Acer spp.). The objective was to find out whether a local management practice could be developed to improve tree care and protection of old urban trees. There was considerable variation between the felling decisions for trees with diverse defects. In addition, a contradiction was found in the criteria for felling decisions between trees with various symptoms, especially between trees with cavities and trees with advanced stages of decay. This contradiction mostly affected Tilia spp.  相似文献   
105.
Journal of Plant Diseases and Protection - Macrophage migration inhibitory factors (MIFs) are multifunctional proteins regulating major processes in mammals, including activation of innate immune...  相似文献   
106.
107.
为明确小麦(Triticum aestivum)-柔软滨麦草(Leymus mollis(Trin.)Hara)易位系M8657-1的抗条锈性,用中国小麦条锈菌(Puccinia striiform f.sp.stritici)流行小种条中30号、条中31号、水源11-4和水源11-11生理小种,对M8657-1和铭贤169的杂交后代进行苗期抗条锈性遗传分析.结果表明,易位系M8657-1对条中30号和水源11-11的抗条锈性均1对隐性核基因控制;对条中31号的抗条锈性由2对显性核基因(互补作用)控制;对水源11-4的抗条锈性由1对显性核基因控制.将控制水源11-4抗病性的基因暂时命名为YrElm1-4,以接种水源11-4的F2正交群体为研究对象,应用BSA法进行了SSR分析.从320对SSR引物组合中筛选到3个与主效抗病基因YrElm1-4连锁的多态性微卫星标记,它们分别是Xgwm636、Xwmc522和Xwmc453,根据3个微卫星标记位点的染色体位置,推出YrElm1-4位于小麦2AS染色体上,这3个标记可用丁分子标记辅助育种.  相似文献   
108.
Polioencephalomalacia was diagnosed histologically in cattle from two herds on the Darling Downs, Queensland, during July–August 2007. In the first incident, 8 of 20 18-month-old Aberdeen Angus steers died while grazing pastures comprising 60% Sisymbrium irio (London rocket) and 40% Capsella bursapastoris (shepherd's purse). In the second incident, 2 of 150 mixed-breed adult cattle died, and another was successfully treated with thiamine, while grazing a pasture comprising almost 100% Raphanus raphanistrum (wild radish). Affected cattle were either found dead or comatose or were seen apparently blind and head-pressing in some cases. For both incidents, plant and water assays were used to calculate the total dietary sulfur content in dry matter as 0.62% and 1.01% respectively, both exceeding the recommended 0.5% for cattle eating more than 40% forage. Blood and tissue assays for lead were negative in both cases. No access to thiaminase, concentrated sodium ion or extrinsic hydrogen sulfide sources were identified in either incident. Below-median late summer and autumn rainfall followed by above-median unseasonal winter rainfall promoted weed growth at the expense of wholesome pasture species before these incidents.  相似文献   
109.
A study was conducted to evaluate the effects of postpartum prostaglandin treatment on reproduction in 3 seasonal calving dairy herds. Recently calved lactating dairy cows were paired on herd, age, calving date and previous production index. One cow in each of the 196 pairs received a single intramuscular injection of 25 mg of the prostaglandin analogue, dinoprost, between 14 and 28 days after calving. Subsequent reproduction was monitored. Within each herd and overall, there was no significant effect of treatment on the intervals from calving to first service, mating start date to first service, calving to conception, mating start date to conception and first service to conception. Treatment also had no significant effect on 21-day submission and pregnancy rates, on the proportion of each group not pregnant at the end of mating, and on first service pregnancy rates. Responses to treatment did not vary between cows calving within 50 days of mating start date and earlier calving cows or between cows aged less than 5 years and older cows.  相似文献   
110.
全内反射荧光法是空间分辨荧光分析技术中重要的部分,该技术突破了传统荧光分析的局限,为获得空间定位信息提供了技术保障.该文系统地综述了全内反射荧光法的原理,特点,发展进程及其应用.引用文献37篇.  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