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   164903篇
  免费   32753篇
  国内免费   2404篇
耳鼻咽喉   5293篇
儿科学   5833篇
妇产科学   2882篇
基础医学   5250篇
口腔科学   1726篇
临床医学   28373篇
内科学   49891篇
皮肤病学   7590篇
神经病学   15874篇
特种医学   6795篇
外国民族医学   3篇
外科学   42612篇
综合类   588篇
现状与发展   72篇
一般理论   11篇
预防医学   8780篇
眼科学   3670篇
药学   2123篇
中国医学   18篇
肿瘤学   12676篇
  2024年   691篇
  2023年   4834篇
  2022年   1258篇
  2021年   3232篇
  2020年   6126篇
  2019年   2349篇
  2018年   7573篇
  2017年   7483篇
  2016年   8577篇
  2015年   8570篇
  2014年   15729篇
  2013年   16002篇
  2012年   5993篇
  2011年   6077篇
  2010年   10694篇
  2009年   14513篇
  2008年   6298篇
  2007年   4559篇
  2006年   6965篇
  2005年   4292篇
  2004年   3555篇
  2003年   2542篇
  2002年   2547篇
  2001年   4299篇
  2000年   3527篇
  1999年   3628篇
  1998年   3818篇
  1997年   3606篇
  1996年   3492篇
  1995年   3363篇
  1994年   2071篇
  1993年   1697篇
  1992年   1769篇
  1991年   1797篇
  1990年   1455篇
  1989年   1515篇
  1988年   1377篇
  1987年   1205篇
  1986年   1195篇
  1985年   1000篇
  1984年   799篇
  1983年   730篇
  1982年   633篇
  1981年   508篇
  1980年   476篇
  1979年   523篇
  1978年   499篇
  1977年   538篇
  1975年   428篇
  1972年   444篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
BACKGROUND: Endothelin, a peptide with strong vasoconstrictive and mitogenic properties, has been found to increase after cardiac transplantation. We therefore assessed the association between its precursor peptide, big endothelin-1, and intimal hyperplasia and coronary flow reserve after heart transplantation. METHODS: Thirty-five patients without hemodynamically significant coronary artery disease after heart transplantation were investigated: Average peak flow velocity in the left anterior descending artery (LAD) was assessed by intracoronary Doppler at baseline as well as after injection of adenosine; coronary flow reserve was calculated as a ratio of both and was corrected for patient age and baseline average peak flow velocity. Lumen, intima + media and total vessel area were measured by intracoronary ultrasound. The plasma concentration of big endothelin-1 in venous blood was determined by radioimmunoassay. RESULTS: Patients with elevated big endothelin-1 levels (>2 fmol/ml) tended to have a decreased corrected coronary flow reserve (2.60 +/- 0.9 vs 3.21 +/- 1.0, p = 0.078). They also had a significantly larger intima + media area (5.82 +/- 2.9 vs 2.37 +/- 2.9 mm(2), p = 0.004) and total vessel area (18.36 +/- 5.8 vs 12.81 +/- 4.8 mm(2), p = 0.012) than those with normal plasma concentrations. CONCLUSIONS: Our study suggests an association between elevated big endothelin-1 plasma levels and the development of intimal hyperplasia and reduction of coronary flow reserve after cardiac transplantation.  相似文献   
65.
66.
67.
OBJECTIVE: To obtain consensus among a panel of experts on performance measures useful for evaluating the quality of hospital-based domestic violence (DV) programs. METHODS: The Delphi process of consensus development was used with a panel of 18 experts including DV researchers, program planners, and advocates. Three rounds were conducted over a period of six months, with each round involving the completion of a written questionnaire. Panelists were instructed to concentrate on structure and process measures of DV program performance. Health outcome measures were not considered. During each round, panelists rated (scale of 1-5) their level of agreement with each measure, in terms of the measure's usefulness for evaluating hospital-based DV programs. Data were entered into SPSS on a personal computer and frequency distributions, measures of central tendency, and variance were computed for each measure. Consensus development was defined as a reduction in the item-specific variance from one round to the next. RESULTS: A total of 37 performance measures were agreed upon. These measures fell within nine different domains of DV program activities, including: Policies and Procedures, Hospital Physical Environment, Hospital Cultural Environment, Training of Providers, Screening and Safety Assessment, Documentation, Intervention Services, Evaluation Activities, and Collaboration. CONCLUSIONS: A number of measures have been identified as useful for evaluating hospital-based DV programs. Use of these measures should assist researchers, program planners, and administrators in assessing the quality of hospital-based DV programs.  相似文献   
68.
This paper reports the proceedings of the discussion panel assigned to look at clinical aspects of quality in emergency medicine. One of the seven stated objectives of the Academic Emergency Medicine consensus conference on quality in emergency medicine was to educate emergency physicians regarding quality measures and quality improvement as essential aspects of the practice of emergency medicine. Another topic of interest was a discussion of the value of information technology in facilitating quality care in the clinical practice of emergency medicine. It is important to note that this is not intended to be a comprehensive review of this extensive topic, but instead is designed to report the discussion that occurred at this session of the consensus conference.  相似文献   
69.
70.
IL2-PE40 is a chimeric protein composed of human interleukin-2 (IL2) genetically fused to a modified form of Pseudomonas exotoxin lacking the cell recognition domain. IL2-PE40 is cytotoxic for IL2 receptor-bearing lymphocytes in culture and can inhibit activation of T cells in vivo. IL2-PE40 can significantly diminish antigen-stimulated proliferation of lymphocytes sensitized to myelin basic protein. Intraperitoneal administration of IL2-PE40 not only markedly inhibits the clinical manifestations of adoptively transferred relapsing experimental allergic encephalomyelitis but also dramatically reduces both inflammation and demyelination characteristic of the disease.  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