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   2418963篇
  免费   160641篇
  国内免费   3427篇
耳鼻咽喉   33069篇
儿科学   77448篇
妇产科学   63755篇
基础医学   354102篇
口腔科学   64884篇
临床医学   216965篇
内科学   468558篇
皮肤病学   52592篇
神经病学   190817篇
特种医学   89762篇
外国民族医学   493篇
外科学   362602篇
综合类   48177篇
现状与发展   12篇
一般理论   931篇
预防医学   187454篇
眼科学   55506篇
药学   178566篇
  68篇
中国医学   4669篇
肿瘤学   132601篇
  2021年   20567篇
  2019年   21418篇
  2018年   28423篇
  2017年   21348篇
  2016年   23738篇
  2015年   26669篇
  2014年   37626篇
  2013年   56208篇
  2012年   78001篇
  2011年   82884篇
  2010年   48996篇
  2009年   46259篇
  2008年   77693篇
  2007年   82792篇
  2006年   83600篇
  2005年   80945篇
  2004年   77443篇
  2003年   74480篇
  2002年   71989篇
  2001年   109094篇
  2000年   111766篇
  1999年   93910篇
  1998年   27522篇
  1997年   24142篇
  1996年   24501篇
  1995年   23092篇
  1994年   21285篇
  1993年   20031篇
  1992年   72264篇
  1991年   70334篇
  1990年   68601篇
  1989年   65857篇
  1988年   60492篇
  1987年   59315篇
  1986年   55417篇
  1985年   53264篇
  1984年   39660篇
  1983年   33671篇
  1982年   20273篇
  1979年   36030篇
  1978年   25868篇
  1977年   21438篇
  1976年   20496篇
  1975年   21990篇
  1974年   26294篇
  1973年   24950篇
  1972年   23324篇
  1971年   22124篇
  1970年   20315篇
  1969年   19381篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
OBJECTIVE: To determine whether under-reporting of rheumatic fever occurs at hospital, municipal, provincial and national levels of the South African health system. BACKGROUND: Information on the incidence of rheumatic fever (RF) and the prevalence of rheumatic heart disease (RHD) is required for the prevention of valvular heart disease in developing countries. In South Africa, RF was made a notifiable condition in 1989. It has recently been suggested that the reporting of RF cases may be incomplete, possibly because of underreporting by health care professionals and deficient administration of the disease notification system in South Africa. METHOD AND RESULTS: We assessed whether underreporting of RF cases occurs by comparing the numbers of RF cases reported per year at hospital, municipal, provincial and national levels from 1990 to 2004. There was a fall in the number of RF cases reported per year at national and provincial level over the 15 years of observation. A detailed analysis of the number of RF cases reported at hospital, municipal and provincial level for a 5-year period showed that more cases were diagnosed in one hospital (serving a smaller population) than were captured at municipal and provincial level (serving a larger population), suggesting underreporting by health care professionals. There were discrepancies in the number of cases reported at municipal, provincial and national level, suggesting poor administration of the notification system. CONCLUSION: There appears to be underreporting of RF cases by health care professionals, and poor administration of the RF notification system. Health care professionals need to be educated about the statutory requirement to notify all RF cases in South Africa. An effective national disease notification system is required.  相似文献   
83.
84.
85.
Traumatic injuries of the elbow are frequent in patients of all ages but are particularly common in young children and adolescents engaged in normal play and athletic competition. Injury may result primarily due to direct trauma or may be secondary to transmission of forces through the elbow following a fall on an outstretched hand. In middle-aged and older individuals, chronic repetitive injuries tend to predominate. In all patients, radiographs remain the initial imaging study of choice. Many patients, however, may need advanced cross-sectional imaging (i.e. MRI, CT, or ultrasound) either at presentation or during the course of their treatment and follow-up. This article reviews the imaging appearance of common acute and chronic traumatic disorders of the elbow.  相似文献   
86.
87.
Both vascular surgery and endovascular interventions traumatise the arterial wall, especially the endothelium. The vessel responds with neointimal hyperplasia and/or constrictive remodelling, and this is still the limiting factor in curative interventions. Stent placement prevents constrictive remodelling but is the main trigger for in-stent restenosis. Hyperproliferation of neointimal tissue is the main response to arterial thrombosis, local inflammation or medio-intimal injury such as occurs, for example, after balloon dilatation in the region of arterial anastomoses or of a thrombectomy (Fogarty-manoeuvre). At present, research on prevention of restenosis is focused on inhibiting neointimal hyperproliferation by using drug-eluting stents, and especially sirolimus- or paclitaxel-eluting stents. In addition, further experimental research work is in progress, with the aim of esablishing new treatment regimens and solving the problem of neointimal formation, thrombosis and constrictive remodelling. These include both local and systemic pharmacological therapy, brachy- and laser therapy, and many genetic treatment options, some of which are currently the subjects of experimental studies and early-stage clinical trials. Gene therapy seems like a promising way of preventing restenosis, but has not yet been tested in clinical trials. In the near future, selective, simultaneous, and perhaps even polyphasic regulation for gene silencing of two or more genes involved in the development of restenosis could improve the long-term patency rate.  相似文献   
88.
89.
90.
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