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   4427821篇
  免费   351158篇
  国内免费   13981篇
耳鼻咽喉   61937篇
儿科学   142442篇
妇产科学   117001篇
基础医学   680680篇
口腔科学   119363篇
临床医学   403307篇
内科学   799489篇
皮肤病学   110961篇
神经病学   364278篇
特种医学   172546篇
外国民族医学   546篇
外科学   680042篇
综合类   123584篇
现状与发展   23篇
一般理论   2617篇
预防医学   369212篇
眼科学   105259篇
药学   310958篇
  23篇
中国医学   11809篇
肿瘤学   216883篇
  2021年   56028篇
  2019年   58634篇
  2018年   74456篇
  2017年   56583篇
  2016年   62659篇
  2015年   75488篇
  2014年   109889篇
  2013年   175206篇
  2012年   127163篇
  2011年   134297篇
  2010年   127558篇
  2009年   127918篇
  2008年   120012篇
  2007年   128680篇
  2006年   136608篇
  2005年   131571篇
  2004年   131724篇
  2003年   122103篇
  2002年   111202篇
  2001年   159905篇
  2000年   155041篇
  1999年   142754篇
  1998年   71260篇
  1997年   66962篇
  1996年   65195篇
  1995年   60424篇
  1994年   54448篇
  1993年   50640篇
  1992年   102542篇
  1991年   99945篇
  1990年   96385篇
  1989年   94126篇
  1988年   86681篇
  1987年   85319篇
  1986年   80259篇
  1985年   79177篇
  1984年   66051篇
  1983年   59030篇
  1982年   47353篇
  1981年   44305篇
  1980年   41688篇
  1979年   57721篇
  1978年   47077篇
  1977年   41183篇
  1976年   38796篇
  1975年   39753篇
  1974年   43393篇
  1973年   41529篇
  1972年   38936篇
  1971年   36360篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
131.
132.
133.
134.
135.
136.
Coronary embolism (CE) is an uncommon and unique cause of acute myocardial infarction. In this report, we review 216 cases of CE including 2 new cases from our institution. The mean patient age was 52.5 years and 62% of the patients were males. Chest pain was the most common presenting symptom followed by dyspnea, and the most commonly affected vessel was the left anterior descending artery. Leading etiologies of the embolus were atrial fibrillation, septic emboli, and iatrogenic causes. Treatment approaches varied with thrombus aspiration being used in 30% of cases. In-hospital mortality rate was 36% and 13% of the cases were complicated by cerebrovascular accident. CE is a unique pathology that leads to acute myocardial infarction. It portends a high mortality rate and requires a high level of suspicion as symptoms may be misleading. Further research is needed in order to improve recognition and management and to lower associated mortality.  相似文献   
137.
Academic output is just one aspect of a successful career as a plastic surgeon. However, for those with a strong interest in academia, the academic output of a department will likely be a key factor when deciding how to rank jobs. The aim of this study was to quantify and rank the academic output of plastic surgery units across the UK and Ireland. The Institute for Scientific Information (ISI) Web of Science Bibliometric analysis tool was used to collate cumulative (1950–2016), 10 year (2006–2016) and 3 years (2013–2015) research output data for plastic surgery units in the UK and Ireland. Sixty-six plastic surgery units were identified. Departments were ranked for each time period according to the number of papers produced, number of citations (Nc) and h-index (a measure of the impact of scientific output). The top 3 departments for number of papers in the last 10 years were The Royal Free Hospital, London (226) Broomfield Hospital, Chelmsford (218), and Morriston Hospital and Swansea (188). The top 3 for h-number were The Royal Free Hospital (21) Wythenshawe Hospital, Manchester (18) and Morriston Hospital (17). Academic output varies across plastic surgery units in the UK and Ireland. A number of departments have consistently maintained high academic outputs across the years and will be of interest to surgeons hoping to pursue a career in academia.  相似文献   
138.
There is a sharp difference in how one views TCR structure–function–behaviour dependent on whether its recognition of major histocompatibility complex‐encoded restriction elements (R) is germline selected or somatically generated. The generally accepted or Standard model is built on the assumption that recognition of R is by the V regions of the αβ TCR, which is not driven by allele specificity, whereas the competing model posits that recognition of R is allele‐specific. The establishing of allele‐specific recognition of R by the TCR would rule out the Standard model and clear the road to a consideration of a competing construct, the Tritope model. Here, the case for allele‐specific recognition (germline selected) is detailed making it obvious that the Standard model is untenable.  相似文献   
139.
140.
Krishna S. Iyer 《Platelets》2020,31(4):474-482
Abstract

Platelets are small, anucleated effector cells that play an important role in linking the hemostatic and inflammatory processes in the body. Platelet function is known to be altered under various inflammatory conditions including aging. A gain in platelet function during aging can increase the risk of thrombotic events, such as stroke and acute myocardial infarction. Anti-platelet therapy is designed to reduce risk of serious cerebrovascular and cardiovascular events, but the adverse consequences of therapy, such as risk for bleeding increases with aging as well. Age-associated comorbidities such as obesity, diabetes, and hyperlipidemia also contribute to increased platelet activity and thus can enhance the risk of thrombosis. Therefore, identification of unique mechanisms of platelet dysfunction in aging and in age-associated comorbidities is warranted to design novel antiplatelet drugs. This review outlines some of the current areas of research on aging-related mechanisms of platelet hyperactivity and addresses the clinical urgency for designing anti-platelet therapies toward novel molecular targets in the aging population.  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