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   126041篇
  免费   8394篇
  国内免费   482篇
耳鼻咽喉   1636篇
儿科学   3437篇
妇产科学   2094篇
基础医学   16160篇
口腔科学   2459篇
临床医学   12693篇
内科学   26620篇
皮肤病学   1964篇
神经病学   11992篇
特种医学   4443篇
外国民族医学   4篇
外科学   18224篇
综合类   1926篇
现状与发展   1篇
一般理论   167篇
预防医学   11204篇
眼科学   2953篇
药学   8750篇
  2篇
中国医学   174篇
肿瘤学   8014篇
  2023年   524篇
  2022年   841篇
  2021年   2083篇
  2020年   1241篇
  2019年   2020篇
  2018年   2362篇
  2017年   1831篇
  2016年   1998篇
  2015年   2471篇
  2014年   3514篇
  2013年   5433篇
  2012年   7801篇
  2011年   8309篇
  2010年   4761篇
  2009年   4597篇
  2008年   7993篇
  2007年   8561篇
  2006年   8395篇
  2005年   8660篇
  2004年   8196篇
  2003年   8011篇
  2002年   7589篇
  2001年   1194篇
  2000年   936篇
  1999年   1252篇
  1998年   1804篇
  1997年   1509篇
  1996年   1259篇
  1995年   1210篇
  1994年   1016篇
  1993年   999篇
  1992年   767篇
  1991年   725篇
  1990年   683篇
  1989年   654篇
  1988年   603篇
  1987年   570篇
  1986年   569篇
  1985年   686篇
  1984年   843篇
  1983年   839篇
  1982年   1182篇
  1981年   1067篇
  1980年   966篇
  1979年   469篇
  1978年   581篇
  1977年   556篇
  1976年   462篇
  1975年   417篇
  1974年   365篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
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   
62.
63.
Patients at Boston's Children's Hospital diagnosed as having cerebral palsy were filmed walking. These films were digitized and translated into measurements associated with leg motion. In this paper we use the gait measurements of 128 such patients to illustrate that the kth nearest neighbour clustering procedure results in a gait typology for patients with cerebral palsy. The procedure identifies four subpopulations from the sample data; the membership of a patient within this typology is mostly determined by the patient's motor control. The developed typology differs from the present diagnostic system which classifies a cerebral palsy patient as either quadriplegic, diaplegic or hemiplegic.  相似文献   
64.
65.
66.
67.
68.
69.
Background: This is the second of two papers using qualitative methods from a study of an intervention for family members affected by close relatives' substance misuse problems.

Participants: 168 primary healthcare professionals (PHCPs: GPs, practice nurses and health visitors) working in general practices in two areas of England, and who took part in the study.

Data sources: Recruitment and post-session forms completed by PHCPs; telephone interviews with each PHCP 12 weeks after recruitment of a family member; interviews with PHCPs at the end of the study.

Results: At the end of the project PHCPs were overwhelmingly positive about the family member intervention and about primary care as the appropriate site. Difficulties were encountered, however, in identifying and engaging affected family members, who were often excluded on grounds of the complexity of their problems or the level of their distress. Shortage of PHCP time and other practice-related factors added to the difficulty. Active work by a PHCP was often necessary in order to make the link between presenting symptoms of physical or mental ill-health and the existence of a family substance misuse problem. When family members were identified and recruited, PHCPs were usually positive about what was achieved. Nearly all were in favour of an approach that combined giving a self-help manual with some follow-up contact with a family member as needed.

Conclusions: Taken in conjunction with statistical outcome findings of significant reductions in symptoms and changes in ways of coping, plus qualitative analysis of the views of family members, the present results encourage the view that a flexible form of this intervention should be developed for use in primary healthcare, and that further work should build on existing strengths and attempt to overcome weaknesses identified.  相似文献   
70.
Celiac Disease   总被引:1,自引:0,他引:1  
  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