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   1905074篇
  免费   138626篇
  国内免费   5375篇
耳鼻咽喉   24602篇
儿科学   62429篇
妇产科学   50666篇
基础医学   284702篇
口腔科学   53023篇
临床医学   180635篇
内科学   364930篇
皮肤病学   39699篇
神经病学   151222篇
特种医学   69315篇
外国民族医学   430篇
外科学   270237篇
综合类   41649篇
现状与发展   3篇
一般理论   603篇
预防医学   155853篇
眼科学   42688篇
药学   142200篇
  9篇
中国医学   5182篇
肿瘤学   108998篇
  2021年   15137篇
  2019年   15821篇
  2018年   22267篇
  2017年   16912篇
  2016年   18450篇
  2015年   21034篇
  2014年   28831篇
  2013年   44238篇
  2012年   60239篇
  2011年   63756篇
  2010年   37201篇
  2009年   34471篇
  2008年   58616篇
  2007年   62155篇
  2006年   62750篇
  2005年   60021篇
  2004年   57601篇
  2003年   54761篇
  2002年   53217篇
  2001年   89236篇
  2000年   91496篇
  1999年   76378篇
  1998年   21057篇
  1997年   18643篇
  1996年   18732篇
  1995年   17787篇
  1994年   16534篇
  1993年   15413篇
  1992年   60105篇
  1991年   58959篇
  1990年   57211篇
  1989年   55119篇
  1988年   50739篇
  1987年   49353篇
  1986年   47019篇
  1985年   44631篇
  1984年   33301篇
  1983年   28375篇
  1982年   16574篇
  1979年   30320篇
  1978年   21434篇
  1977年   17776篇
  1976年   17284篇
  1975年   18132篇
  1974年   21935篇
  1973年   21291篇
  1972年   19789篇
  1971年   18417篇
  1970年   17306篇
  1969年   15838篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
A true comparison of long-term medical and surgical treatment in gastro-oesophageal reflux disease (GORD) is impossible as few studies have been carried out with adequate randomisation of the patients and long-term evaluation of quality of life. In general the control of the reflux symptoms is roughly equal with medical and surgical treatment. However, surgery can cause other symptoms such as dysphagia or non-specific epigastric discomfort or pain in some patients, which reduces the overall efficacy in controlling the symptoms. Based on a cost utility analysis, Heudebert et al. came to the conclusion that medical treatment was their preferred strategy for most patients with severe erosive oesophagitis.  相似文献   
103.
104.
The prevalence of heavy alcohol consumption is a major problem of increasing proportions throughout the world. Although alcohol sensitizing drugs and more recently serotonin uptake inhibitors are drug interventions with some following, their long term beneficial consequences have yet to be demonstrated. In recent years, we have demonstrated that manipulating activity in the renin-angiotensin system will dramatically alter voluntary alcohol consumption in rats. Based on these findings, the present study evaluated the ability of a class of drugs known as the angiotensin converting enzyme inhibitors to reduce voluntary alcohol drinking in laboratory animals. These drugs prevent the conversion of angiotensin I to angiotensin II. They have been licensed for use in Europe and North America and are indicated in the treatment of hypertension. Our experiments showed that both captopril (Capoten, Squibb) and enalapril (Vasotec, Merck Sharpe & Dohme) can reduce alcohol drinking in both normotensive and hypertensive animals regardless of whether the pattern of intake is in a bout or of a less exaggerated nature. Furthermore, this change in alcohol intake can occur without concomitant changes in blood pressure, plasma renin activity, overall fluid balance, or the distribution and metabolism of alcohol. Taken together these findings suggest that the angiotensin converting enzyme inhibitors should be evaluated in a clinical setting for they may prove to be a useful new treatment or treatment adjunct for alcohol abuse in humans.  相似文献   
105.
106.
107.
108.
Fibroblasts incorporated within collagen gels induce a cell-mediated contraction of the gel to form a three-dimensional, tissue-like structure by a mechanism thought to mimic wound contraction in vivo . In this study a gel contraction model was used to investigate the ability of fibroblasts derived from adult gingiva, adult skin and fetal skin to organise a collagen matrix. In addition the effects of interleukin-1β (IL-1β) on the contraction process was also investigated. Over the concentration range 5-50 U/ml, IL-1β induced a statistically significant inhibition of gel contraction in all fibroblast cell types ( P <0.05), although fetal fibroblasts appeared least responsive and gingival fibroblasts most responsive to the inhibitory effects of this cytokine. Comparison of gel contraction by the different fibroblast strains indicated that fetal and gingival fibroblasts shared similar contraction kinetics. For the adult skin fibroblasts, three of five strains studied showed significantly diminished levels of gel contraction compared to fetal and gingival cells. This apparent difference in fibroblast phenotype may, at least in part, explain the fetal-like wound healing pattern seen in the oral mucosa.  相似文献   
109.
110.
Tissue specimens from the large bowel of 18 patients with long-standing slow transit constipation were investigated to determine the distribution and density of several neuropeptides and amines in the enteric nerve system, and also of endocrine cells in comparison to normal individuals. CGRP (calcitonin gene-related peptide), galanin, glucagon, GRP (gastrin-releasing peptide), metenkephalin, motilin, neuropeptide Y (NPY), PACAP, peptide YY (PYY), serotonin, somatostatin, substance P and VIP were studied by immunohistochemistry. Tissue concentrations of VIP, substance P and galanin were also measured by radioimmunoassay. Significantly increased VIP, SP and galanin contents were found in specimens from the ascending colon. Levels of VIP and galanin were also increased in the transverse colon. Immunohistochemistry revealed only marginal changes with an increased density of PACAP nerve fibres in the smooth muscle and of VIP and PACAP nerves in the myenteric plexus of the transverse colon. In the descending colon substance P and NPY immunoreactivity were also increased in the myenteric plexus while the density of VIP nerve fibres was reduced in the mucosa/submucosa. The frequency of PYY-containing cells and the 5-HT-containing cells in the ascending colon was significantly increased in the constipated patients.  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