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   2368876篇
  免费   173115篇
  国内免费   3370篇
耳鼻咽喉   32378篇
儿科学   76735篇
妇产科学   63342篇
基础医学   351373篇
口腔科学   64035篇
临床医学   212993篇
内科学   460913篇
皮肤病学   52137篇
神经病学   187344篇
特种医学   88805篇
外国民族医学   503篇
外科学   356610篇
综合类   47605篇
现状与发展   12篇
一般理论   850篇
预防医学   183784篇
眼科学   54749篇
药学   176158篇
  11篇
中国医学   4587篇
肿瘤学   130437篇
  2021年   19266篇
  2019年   19791篇
  2018年   27371篇
  2017年   20624篇
  2016年   23120篇
  2015年   25991篇
  2014年   36571篇
  2013年   54607篇
  2012年   75548篇
  2011年   80375篇
  2010年   47557篇
  2009年   45082篇
  2008年   75522篇
  2007年   80431篇
  2006年   81205篇
  2005年   78680篇
  2004年   75116篇
  2003年   72472篇
  2002年   70091篇
  2001年   109274篇
  2000年   111999篇
  1999年   93983篇
  1998年   27241篇
  1997年   23850篇
  1996年   24208篇
  1995年   22854篇
  1994年   21023篇
  1993年   19834篇
  1992年   72295篇
  1991年   70424篇
  1990年   68719篇
  1989年   65932篇
  1988年   60564篇
  1987年   59390篇
  1986年   55480篇
  1985年   53252篇
  1984年   39493篇
  1983年   33545篇
  1982年   19950篇
  1979年   36067篇
  1978年   25789篇
  1977年   21344篇
  1976年   20451篇
  1975年   21948篇
  1974年   26316篇
  1973年   24945篇
  1972年   23328篇
  1971年   22145篇
  1970年   20344篇
  1969年   19400篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
Dosage form is a mean used for the delivery of drug to a living body. In order to get the desired effect the drug should be delivered to its site of action at such rate and concentration to achieve the maximum therapeutic effect and minimum adverse effect. Since oral route is still widely accepted route but having a common drawback of difficulty in swallowing of tablets and capsules. Therefore a lot of research has been done on novel drug delivery systems. This review is about oral dispersible tablets a novel approach in drug delivery systems that are now a day''s more focused in formulation world, and laid a new path that, helped the patients to build their compliance level with the therapy, also reduced the cost and ease the administration especially in case of pediatrics and geriatrics. Quick absorption, rapid onset of action and reduction in drug loss properties are the basic advantages of this dosage form.  相似文献   
42.
43.
Hepatic NADPH-cytochrome P450 oxidoreductase null (HRN?) mice exhibit normal hepatic and extrahepatic biotransformation enzyme activities when compared to wild-type (WT) mice, but express no functional hepatic cytochrome P450 activities. When incubated in vitro with [14C]-diclofenac, liver microsomes from WT mice exhibited extensive biotransformation to oxidative and glucuronide metabolites and covalent binding to proteins was also observed. In contrast, whereas glucuronide conjugates and a quinone-imine metabolite were formed when [14C]-diclofenac was incubated with HRN? mouse liver, only small quantities of P450-derived oxidative metabolites were produced in these samples and covalent binding to proteins was not observed. Livers from vehicle-treated HRN? mice exhibited enhanced lipid accumulation, bile duct proliferation, hepatocellular degeneration and necrosis and inflammatory cell infiltration, which were not present in livers from WT mice. Elevated liver-derived alanine aminotransferase, glutamate dehydrogenase and alkaline phosphatase activities were also observed in plasma from HRN? mice. When treated orally with diclofenac for 7 days, at 30 mg/kg/day, the severities of the abnormal liver histopathology and plasma liver enzyme findings in HRN? mice were reduced markedly. Oral diclofenac administration did not alter the liver histopathology or elevate plasma enzyme activities of WT mice. These findings indicate that HRN? mice are valuable for exploration of the role played by hepatic P450s in drug biotransformation, but poorly suited to investigations of drug-induced liver toxicity. Nevertheless, studies in HRN? mice could provide novel insights into the role played by inflammation in liver injury and may aid the evaluation of new strategies for its treatment.  相似文献   
44.
45.
46.
47.
48.
49.
Nidogen 1 (NID1) is a glycoprotein found in basement membranes involved in cross-linking collagen IV and laminin. The role of NID in breast cancer has only been evaluated in a small number of studies and the findings of these studies have been inconsistent. Our previous work revealed that highly tumorigenic murine mammary tumor cells express high levels of Nid1 while weakly tumorigenic mammary tumor cells express low levels of Nid1. To investigate Nid1, two stable knockdown lines were created, and Nid1 knockdown was confirmed at both the mRNA and protein level. Nid1 knockdown significantly reduced cell proliferation and migration/invasion and these reductions in proliferation and migration/invasion could be rescued by conditioned media containing NID1 protein. The reduced migration/invasion observed in the Nid1 knockdown cells was not associated with significant alterations in the epithelial gene Cdh1 or the mesenchymal genes Snai1, Snai2, Twist1, Twist2, Zeb1 and Zeb2. Therefore, suppression of Nid1 expression reduces proliferation and migration/invasion in claudin-low murine mammary tumor cells.  相似文献   
50.
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