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   106612篇
  免费   8010篇
  国内免费   7389篇
  2024年   149篇
  2023年   1233篇
  2022年   2266篇
  2021年   5482篇
  2020年   3676篇
  2019年   4610篇
  2018年   4560篇
  2017年   3311篇
  2016年   4687篇
  2015年   6696篇
  2014年   7911篇
  2013年   8389篇
  2012年   9776篇
  2011年   8980篇
  2010年   5304篇
  2009年   4908篇
  2008年   5642篇
  2007年   4937篇
  2006年   4219篇
  2005年   3440篇
  2004年   2798篇
  2003年   2560篇
  2002年   2080篇
  2001年   1763篇
  2000年   1639篇
  1999年   1701篇
  1998年   982篇
  1997年   1044篇
  1996年   975篇
  1995年   921篇
  1994年   820篇
  1993年   671篇
  1992年   823篇
  1991年   639篇
  1990年   552篇
  1989年   406篇
  1988年   328篇
  1987年   259篇
  1986年   217篇
  1985年   237篇
  1984年   140篇
  1983年   131篇
  1982年   70篇
  1981年   30篇
  1980年   23篇
  1979年   20篇
  1976年   1篇
  1975年   2篇
  1966年   1篇
  1950年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Abstract Field trials by sex pheromone of aphid to trap peach aphids Myzus persicae have been carried out in 1995 and in 1996. Suitable time and the effect of ratio of two components nepetalactone and nepetalactol to apply the lure have been observed.  相似文献   
82.
83.
84.
A cDNA clone encoding the N-terminal sequence of the murine integrin beta 7 subunit, a novel member of the leukocyte cell adhesion molecule subset (Leu-CAM), has been isolated. An N-terminal region of 13 contiguous amino acids deduced from the cDNA shows complete identity with the N-terminus of the 120 kDa subunit of the M290 antigen, a surface molecule found highly expressed on mouse intestinal intraepithelial lymphocytes (IEL). This unexpected result focuses two previously unconnected areas of research and suggests that integrins may have a special role to play in the defence of the gut mucosa.  相似文献   
85.
International Journal of Peptide Research and Therapeutics - A novel peroxidase has been isolated from fresh fruiting bodies of the mushroom Pleurotus pulmonarius, with a purification protocol of...  相似文献   
86.
87.
We previously identified heme oxygenase 1 (HO-1) as a specific target of miR-155, and inhibition of HO-1 activity restored the capacity of miR-155 -/- CD4+ T cells to promote antigen-driven inflammation after adoptive transfer in antigen-expressing recipients. Protoporphyrins are molecules recognized for their modulatory effect on HO-1 expression and function. In the present study, we investigated the effect of protoporphyrin treatment on the development of autoimmunity in miR-155-deficient mice. MiR-155-mediated control of HO-1 expression in promoting T cell-driven chronic autoimmunity was confirmed since HO-1 inhibition restored susceptibility to experimental autoimmune encephalomyelitis (EAE) in miR-155-deficient mice. The increased severity of the disease was accompanied by an enhanced T cell infiltration into the brain. Taken together, these results underline the importance of miR-155-mediated control of HO-1 expression in regulating the function of chronically-stimulated T cells in EAE.  相似文献   
88.
Small molecule cholinesterases inhibitor (ChEI) provides an effective therapeutic strategy to treat Alzheimer’s disease (AD). Currently, the discovery of new ChEI with multi-target effect is still of great importance. Herein, we report the synthesis, structure–activity relationship study and biological evaluation of a series of tacrine-cinnamic acid hybrids as new ChEIs. All target compounds are evaluated for their in vitro cholinesterase inhibitory activities. The representatives which show potent activity on cholinesterase, are evaluated for the amyloid β-protein self-aggregation inhibition and in vivo assays. The optimal compound 19, 27, and 30 (human AChE IC50?=?10.2?±?1.2, 16.5?±?1.7, and 15.3?±?1.8?nM, respectively) show good performance in ameliorating the scopolamine-induced cognition impairment and preliminary safety in hepatotoxicity evaluation. These compounds deserve further evaluation for the development of new therapeutic agents against AD.  相似文献   
89.
90.
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