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   2970168篇
  免费   213365篇
  国内免费   4419篇
耳鼻咽喉   41531篇
儿科学   92032篇
妇产科学   78971篇
基础医学   432757篇
口腔科学   84488篇
临床医学   266590篇
内科学   573875篇
皮肤病学   64493篇
神经病学   233615篇
特种医学   112393篇
外国民族医学   557篇
外科学   455447篇
综合类   60829篇
现状与发展   12篇
一般理论   1029篇
预防医学   224851篇
眼科学   69576篇
药学   223849篇
  14篇
中国医学   6025篇
肿瘤学   165018篇
  2019年   23008篇
  2018年   32255篇
  2017年   24390篇
  2016年   27441篇
  2015年   30854篇
  2014年   43407篇
  2013年   64956篇
  2012年   89345篇
  2011年   94702篇
  2010年   56307篇
  2009年   53383篇
  2008年   89830篇
  2007年   95530篇
  2006年   96871篇
  2005年   93797篇
  2004年   89876篇
  2003年   86644篇
  2002年   84219篇
  2001年   142731篇
  2000年   146742篇
  1999年   123302篇
  1998年   34148篇
  1997年   29889篇
  1996年   30149篇
  1995年   28459篇
  1994年   26242篇
  1993年   24556篇
  1992年   95488篇
  1991年   92636篇
  1990年   90454篇
  1989年   87246篇
  1988年   80058篇
  1987年   78502篇
  1986年   73291篇
  1985年   70569篇
  1984年   51850篇
  1983年   44145篇
  1982年   25286篇
  1979年   47189篇
  1978年   33181篇
  1977年   27806篇
  1976年   26024篇
  1975年   28175篇
  1974年   34014篇
  1973年   32255篇
  1972年   30329篇
  1971年   28794篇
  1970年   26803篇
  1969年   25510篇
  1968年   23240篇
排序方式: 共有10000条查询结果,搜索用时 15 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.
50.
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   
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