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   2474917篇
  免费   196865篇
  国内免费   5305篇
耳鼻咽喉   36309篇
儿科学   80429篇
妇产科学   64625篇
基础医学   350850篇
口腔科学   64943篇
临床医学   234245篇
内科学   495751篇
皮肤病学   58245篇
神经病学   197572篇
特种医学   93297篇
外国民族医学   489篇
外科学   387569篇
综合类   47735篇
现状与发展   84篇
一般理论   849篇
预防医学   188531篇
眼科学   57230篇
药学   175965篇
  11篇
中国医学   4583篇
肿瘤学   137775篇
  2021年   21476篇
  2019年   21249篇
  2018年   33165篇
  2017年   26424篇
  2016年   29535篇
  2015年   32522篇
  2014年   48880篇
  2013年   66970篇
  2012年   79209篇
  2011年   84020篇
  2010年   55686篇
  2009年   56338篇
  2008年   79440篇
  2007年   82878篇
  2006年   85760篇
  2005年   80937篇
  2004年   76914篇
  2003年   73353篇
  2002年   71094篇
  2001年   111883篇
  2000年   113979篇
  1999年   96144篇
  1998年   29964篇
  1997年   26464篇
  1996年   26723篇
  1995年   25318篇
  1994年   22432篇
  1993年   20961篇
  1992年   73108篇
  1991年   71248篇
  1990年   69265篇
  1989年   66612篇
  1988年   61126篇
  1987年   59849篇
  1986年   55964篇
  1985年   53593篇
  1984年   39760篇
  1983年   33816篇
  1982年   20273篇
  1979年   36110篇
  1978年   25922篇
  1977年   21546篇
  1976年   20537篇
  1975年   22051篇
  1974年   26332篇
  1973年   24998篇
  1972年   23463篇
  1971年   22191篇
  1970年   20458篇
  1969年   19377篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
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   
95.
96.
97.
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   
98.
99.
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   
100.
CONTEXT: The physician assistant profession has been moving toward requiring master's degrees for new practitioners, but some argue this could change the face of the discipline. PURPOSE: To see if there is an association between physician assistants' academic degrees and practice in primary care, in rural areas, and with the medically underserved. METHODS: Surveys were sent to 880 graduates of the first 32 University of Washington physician assistant classes through 2000. Respondents noted their academic degree at program entry and the highest degree attained at any time up to the time of survey. Relationships between practice characteristics and academic degree levels were tested by unadjusted odds ratios and logistic regression after controlling for year of graduation and sex. RESULTS: Of the 478 respondents, 54% worked in primary care, about 30% practiced in nonmetropolitan communities, and 42% reported providing care for the medically underserved. Respondents with no degree (33% of total at entry, 24% at survey) were significantly more likely than degree holders to work in primary care and nonmetropolitan areas. Respondents with no degree at program entry were significantly more likely, and those with no degree at the time of the survey were marginally more likely, to self-report work with the medically underserved. CONCLUSION: Respondents with no academic degree are significantly more likely to demonstrate a commitment to primary, rural, and underserved health care. These findings may inform the national debate about the impact of required advanced degrees on the practice patterns of nonphysician providers.  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