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   1489083篇
  免费   122298篇
  国内免费   6794篇
耳鼻咽喉   18888篇
儿科学   47218篇
妇产科学   39419篇
基础医学   203682篇
口腔科学   39394篇
临床医学   135568篇
内科学   309694篇
皮肤病学   34242篇
神经病学   125715篇
特种医学   60585篇
外国民族医学   286篇
外科学   232121篇
综合类   33579篇
现状与发展   5篇
一般理论   596篇
预防医学   118087篇
眼科学   32278篇
药学   103697篇
  5篇
中国医学   2405篇
肿瘤学   80711篇
  2019年   11462篇
  2018年   16204篇
  2017年   12676篇
  2016年   15189篇
  2015年   17211篇
  2014年   24208篇
  2013年   36428篇
  2012年   45835篇
  2011年   49228篇
  2010年   30194篇
  2009年   29266篇
  2008年   46239篇
  2007年   49328篇
  2006年   50003篇
  2005年   48843篇
  2004年   46618篇
  2003年   45205篇
  2002年   42961篇
  2001年   67286篇
  2000年   68820篇
  1999年   57887篇
  1998年   18678篇
  1997年   16685篇
  1996年   17421篇
  1995年   17465篇
  1994年   16260篇
  1993年   15238篇
  1992年   47895篇
  1991年   46461篇
  1990年   44605篇
  1989年   42451篇
  1988年   39393篇
  1987年   38608篇
  1986年   36474篇
  1985年   35329篇
  1984年   27331篇
  1983年   23044篇
  1982年   15200篇
  1981年   13697篇
  1980年   12906篇
  1979年   24177篇
  1978年   17793篇
  1977年   15024篇
  1976年   13737篇
  1975年   14191篇
  1974年   16585篇
  1973年   15785篇
  1972年   14486篇
  1971年   13249篇
  1970年   12061篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction.  相似文献   
64.
65.
66.
67.
68.
High levels of tumor necrosis factor-alpha (TNF-alpha), a pro-inflammatory cytokine, are present in the wound fluid of chronic nonhealing wounds. This leads to increased inflammation, cytokine expression, and ultimately results in impaired wound healing and tissue destruction. Etanercept is a recombinant fusion protein that consists of the soluble TNF receptor (p75) linked to the Fc portion of human IgG1. It is an effective inhibitor of TNF-alpha and has been shown to provide rapid and sustained improvement in rheumatoid arthritis by acting as a soluble receptor binding TNF-alpha and preventing its proinflammatory activities. Therefore, the aim of this study was to determine whether Etanercept could inhibit TNF-alpha activity in chronic wound fluid. Wound fluid was collected from the venous leg ulcers of 16 different patients. The effect of Etanercept on TNF-alpha activity was evaluated using both a TNF-alpha bioassay and an enzyme-linked immunoassay. Etanercept was found to reduce the cytotoxic effect of chronic wound fluid on L929 fibroblasts by approximately 30% and neutralized TNF-alpha binding in the enzyme-linked immunoassay by up to 80%. Direct application of Etanercept to chronic wounds may therefore reduce the inflammatory activity of TNF-alpha, which could reduce the chronicity of venous leg ulcers and thus aid in the healing of these wounds.  相似文献   
69.
For many parents stopping life-sustaining medical treatment on their dying infant is psychologically impossible. Dostoevsky's insights into human behavior, particularly the fact that individuals do not want the anxiety and guilt associated with responsibility for making difficult decisions, might change the way physicians approach parents for permission to withdraw life-prolonging medical interventions on dying infants.  相似文献   
70.
Four clinical trials of porcine islet transplantation have been reported, and there are verbal reports that clinical trials on much larger scales are continuing in centers in China and Russia. The four reported trials are briefly reviewed and, in the light of the present status of experimental islet xenotransplantation, consideration is given to whether such trials are currently justified. The Ethics Committee of the International Xenotransplantation Association has (1) emphasized the need for encouraging studies in non-human primates before clinical trials should be undertaken, (2) mandatory monitoring for the transfer of porcine microorganisms, and (3) careful regulation and oversight by recognized bodies. Other aspects of the topic, such as the need for informed consent, are briefly discussed. We conclude that, at the present time, more data documenting convincing efficacy, focused on clinically applicable immunosuppressive regimens, are needed to justify the initiation of closely monitored clinical trials. A clinical trial may then be justified even though the potential risk to the patients, and possibly for society, will not be zero.  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