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   164篇
  免费   16篇
林业   1篇
农学   1篇
  1篇
综合类   13篇
农作物   2篇
水产渔业   4篇
畜牧兽医   146篇
园艺   2篇
植物保护   10篇
  2021年   1篇
  2020年   4篇
  2019年   6篇
  2018年   6篇
  2017年   4篇
  2016年   4篇
  2015年   5篇
  2014年   9篇
  2013年   29篇
  2012年   4篇
  2011年   4篇
  2010年   12篇
  2009年   9篇
  2007年   5篇
  2006年   2篇
  2005年   2篇
  2004年   1篇
  2003年   5篇
  2002年   6篇
  2001年   5篇
  2000年   2篇
  1999年   2篇
  1998年   15篇
  1997年   11篇
  1996年   8篇
  1995年   2篇
  1994年   3篇
  1993年   3篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   1篇
排序方式: 共有180条查询结果,搜索用时 31 毫秒
171.
172.
173.
Ostrich meat was originally considered to be a by-product of the leather industry. Ostrich farming focused on the production of good quality hides and was mainly based on experience. Since a few years there has been a move from hide production to meat production; however, little is known about ostrich meat production which has consequences for legislation. There is insufficient knowledge about the factors influencing muscle growth. The strong growth of ostrich meat production in the EU member states should be discussed because the climatic conditions are not optimal and the price of the meat may remain high compared to meat of broilers, pigs, and cattle. Information programmes have to be set up for all members in the production chain. The present method for stunning of ostriches has to be changed in most slaughterhouses. In this study the effects of electrical and mechanical stunning on unconsciousness, duration of unconsciousness, behaviour, and meat quality parameters were examined. At least 500 mA is needed to stun ostriches effectively, and they can be killed using a short-stick interval or a long stunning duration. A modified captive needle pistol, using air pressure, is an alternative to electrical head-only stunning.  相似文献   
174.
175.
Poisoning with Senecio jacobaea (ragwort) is a common cause of chronic liver disease in horses in Britain. The major clinical signs are the result of hepatic failure but gastric impaction has recently been associated with the disease. The present paper describes three cases of secondary gastric impaction associated with ragwort poisoning. In each case the impaction was the cause of death or necessitated euthanasia.  相似文献   
176.
Cryopreservation of Sheep Primordial Follicles   总被引:3,自引:0,他引:3  
The aim of this study was to evaluate the efficiency of 1 M dimethylsulphoxide (DMSO), ethylene glycol (EG), propylene glycol (PROH) and glycerol (GLY) to cryopreserve primordial follicles. The first evaluation was performed soon after cryopreservation and the second evaluation after 4 days of in vitro culture, using the cryoprotectants that allowed the higher results (higher follicular survival rate) after cryopreservation. The results after follicular isolation (control) and cryopreservation using 1 M DMSO, EG, PROH and GLY showed that the mean number (+/- SEM) of live follicles per millilitre was 3204 (100%) +/- 319.27, 2798 (87%) +/- 239.14, 2492 (78%) +/- 345.8, 448 (14%) +/- 46.3 and 208 (7%) +/- 75.26, respectively. Higher follicular survival was reported when DMSO and EG were used. Control follicles and follicles cryopreserved with these two cryoprotectants were cultured and the percentage of follicular survival was 55% (control), 42% (EG) and 34% (DMSO). Similar results were found between control and follicles cryopreserved with EG. In conclusion, 1 M EG is the most effective cryoprotectant to preserve primordial follicles isolated from ovaries of sheep.  相似文献   
177.

Background  

Kinome profiling aims at the parallel analysis of kinase activities in a cell. Novel developed arrays containing consensus substrates for kinases are used to assess those kinase activities. The arrays described in this paper were already used to determine kinase activities in mammalian systems, but since substrates from many organisms are present we decided to test these arrays for the determination of kinase activities in the model plant species Arabidopsis thaliana.  相似文献   
178.
The ground and excited state spectra of a semiconductor quantum dot with successive electron occupancy were studied with linear and nonlinear magnetoconductance measurements. A direct correlation was observed between the mth excited state of the N-electron system and the ground state of the (N + m)-electron system for m up to 4. The results are consistent with a single-particle picture in which a fixed spectrum of energy levels is successively filled, except for a notable absence of spin degeneracy. Further departures from the single-particle picture due to electron-electron interaction were also observed. Magnetoconductance fluctuations of ground states show anticrossings where wave function characteristics are exchanged between adjacent levels.  相似文献   
179.

Background  

The fertilization success in sperm competition in externally fertilizing fish depends on number and quality of sperm. The time delay between sequential ejaculations may further influence the outcome of sperm competition. Such a time interval can load the raffle over fertilization if fertilization takes place very fast. Short fertilization times are generally assumed for externally fertilizing fish such as the three-spined stickleback (Gasterosteus aculeatus). In this pair-spawning fish, territorial males often try to steal fertilizations in nests of neighbouring males. This sneaking behaviour causes sperm competition. Sneakers will only get a share of paternity when eggs are not fertilized immediately after sperm release. Contrary to males, females may be interested in multiple paternity of their clutch of eggs. There thus may be a sexual conflict over the speed of fertilization.  相似文献   
180.
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