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   537876篇
  免费   60041篇
  国内免费   336篇
  2018年   5323篇
  2017年   5219篇
  2016年   7087篇
  2015年   8869篇
  2014年   10622篇
  2013年   15504篇
  2012年   17375篇
  2011年   17824篇
  2010年   11948篇
  2009年   10881篇
  2008年   15487篇
  2007年   16102篇
  2006年   15009篇
  2005年   14357篇
  2004年   14206篇
  2003年   13574篇
  2002年   13080篇
  2001年   28506篇
  2000年   28399篇
  1999年   22075篇
  1998年   6778篇
  1997年   7352篇
  1996年   6793篇
  1995年   6251篇
  1994年   6032篇
  1993年   6011篇
  1992年   17078篇
  1991年   16329篇
  1990年   15738篇
  1989年   15247篇
  1988年   13956篇
  1987年   12964篇
  1986年   12081篇
  1985年   11858篇
  1984年   9702篇
  1983年   8129篇
  1982年   6038篇
  1981年   5416篇
  1980年   5144篇
  1979年   8975篇
  1978年   6849篇
  1977年   6317篇
  1976年   5676篇
  1975年   6257篇
  1974年   6772篇
  1973年   6562篇
  1972年   5988篇
  1971年   5438篇
  1970年   4683篇
  1969年   4402篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
A study was made of the fatty acid composition and the content of triglycerides, phospholipids and nonesterified fatty acids (NFA) in adipose and muscle tissues of rats with alloxan diabetes. The concentration of NFA in alloxan diabetes was found to be considerably reduced in both adipose and muscle tissues. Meanwhile the content of NFA and phospholipids did not experience any substantial changes. The fatty acid composition of triglycerides of the tissues under study was characterized by considerable alterations under diabetes.  相似文献   
973.
974.
The effect of different chemical anxiolytic agents on ethanol consumption has been studied on the model of experimental alcoholism in rats. The decrease of ethanol consumption was dose-dependent. The existence of non-benzodiazepine anxiolytic systems is suggested.  相似文献   
975.
976.
Actin is a major antigen involved in the reaction of smooth muscle antibody positive sera from patients with chronic active hepatitis. In the present study, actin extracted from rabbit skeletal muscle was denatured by sodium dodecyl sulfate and was immunized into the rabbit, a homologous animal for actin. The rabbits, thus immunized, produced antibodies reactive with actins of homologous and heterologous animals. In addition, the antibodies showed reactivity with autologous actin. It indicates that the denatured homologous actin is capable of terminating immunological tolerance to actin and induces formation of autoantibody to rabbit actin. This phenomenon may be implicated in the occurrence of anti-actin antibody in sera from patients with chronic liver disease and several other diseases.  相似文献   
977.
978.
979.
980.
Mechanism of mda-5 Inhibition by Paramyxovirus V Proteins   总被引:1,自引:0,他引:1       下载免费PDF全文
The RNA helicases encoded by melanoma differentiation-associated gene 5 (mda-5) and retinoic acid-inducible gene I (RIG-I) detect foreign cytoplasmic RNA molecules generated during the course of a virus infection, and their activation leads to induction of type I interferon synthesis. Paramyxoviruses limit the amount of interferon produced by infected cells through the action of their V protein, which binds to and inhibits mda-5. Here we show that activation of both mda-5 and RIG-I by double-stranded RNA (dsRNA) leads to the formation of homo-oligomers through self-association of the helicase domains. We identify a region within the helicase domain of mda-5 that is targeted by all paramyxovirus V proteins and demonstrate that they inhibit activation of mda-5 by blocking dsRNA binding and consequent self-association. In addition to this commonly targeted domain, some paramyxovirus V proteins target additional regions of mda-5. In contrast, V proteins cannot bind to RIG-I and consequently have no effect on the ability of RIG-I to bind dsRNA or to form oligomers.  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