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   47717篇
  免费   3889篇
  国内免费   3392篇
  2023年   530篇
  2022年   757篇
  2021年   2072篇
  2020年   1547篇
  2019年   1947篇
  2018年   2077篇
  2017年   1709篇
  2016年   2201篇
  2015年   2556篇
  2014年   3272篇
  2013年   3530篇
  2012年   4024篇
  2011年   3746篇
  2010年   2639篇
  2009年   2328篇
  2008年   2677篇
  2007年   2391篇
  2006年   2079篇
  2005年   1717篇
  2004年   1610篇
  2003年   1514篇
  2002年   1236篇
  2001年   1006篇
  2000年   839篇
  1999年   614篇
  1998年   381篇
  1997年   315篇
  1996年   299篇
  1995年   323篇
  1994年   297篇
  1993年   226篇
  1992年   293篇
  1991年   261篇
  1990年   208篇
  1989年   192篇
  1988年   129篇
  1987年   175篇
  1986年   145篇
  1985年   128篇
  1984年   101篇
  1983年   95篇
  1982年   82篇
  1981年   78篇
  1980年   52篇
  1979年   62篇
  1978年   66篇
  1977年   49篇
  1976年   50篇
  1973年   63篇
  1972年   52篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Salmonella enterica serovar Enteritidis (SE) is a foodborne pathogen that can threaten human health through contaminated poultry products. Live poultry, chicken eggs and meat are primary sources of human salmonellosis. To understand the genetic resistance of egg‐type chickens in response to SE inoculation, global gene expression in the spleen of 20‐week‐old White Leghorn was measured using the Agilent 4 × 44 K chicken microarray at 7 and 14 days following SE inoculation (dpi). Results showed that there were 1363 genes significantly differentially expressed between inoculated and non‐inoculated groups at 7 dpi (I7/N7), of which 682 were up‐regulated and 681 were down‐regulated genes. By contrast, 688 differentially expressed genes were observed at 14 dpi (I14/N14), of which 371 were up‐regulated genes and 317 were down‐regulated genes. There were 33 and 28 immune‐related genes significantly differentially expressed in the comparisons of I7/N7 and I14/N14 respectively. Functional annotation revealed that several Gene Ontology (GO) terms related to immunity were significantly enriched between the inoculated and non‐inoculated groups at 14 dpi but not at 7 dpi, despite a similar number of immune‐related genes identified between I7/N7 and I14/N14. The immune response to SE inoculation changes with different time points following SE inoculation. The complicated interaction between the immune system and metabolism contributes to the immune responses to SE inoculation of egg‐type chickens at 14 dpi at the onset of lay. GC, TNFSF8, CD86, CD274, BLB1 and BLB2 play important roles in response to SE inoculation. The results from this study will deepen the current understanding of the genetic response of the egg‐type chicken to SE inoculation at the onset of egg laying.  相似文献   
2.
3.
4.
The conditions to obtain materials with elastic-viscous properties based on chitosan succinamide have been studied. A decreased polymer content and a transition from visco-elastic liquids to elastic-viscous systems were shown upon the addition of glycerol to an aqueous solution of chitosan succinamide. The systemic response, biological compatibility, and dynamics of bioresorbability of the obtained materials were studied during implantation in laboratory animals.  相似文献   
5.
6.
7.
8.
9.
10.
Plasma Physics Reports - It is shown theoretically that under the effect of plasma flows typical of transient processes in tokamaks not only can Kelvin–Helmholtz instability develop and waves...  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