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   5264407篇
  免费   412845篇
  国内免费   16337篇
耳鼻咽喉   75811篇
儿科学   163113篇
妇产科学   140273篇
基础医学   781158篇
口腔科学   151979篇
临床医学   485262篇
内科学   960308篇
皮肤病学   121872篇
神经病学   438367篇
特种医学   206780篇
外国民族医学   1178篇
外科学   795595篇
综合类   148554篇
现状与发展   24篇
一般理论   2968篇
预防医学   442797篇
眼科学   126412篇
药学   378174篇
  30篇
中国医学   13485篇
肿瘤学   259449篇
  2021年   56530篇
  2019年   59201篇
  2018年   75925篇
  2017年   58194篇
  2016年   64653篇
  2015年   77181篇
  2014年   112092篇
  2013年   177595篇
  2012年   144754篇
  2011年   153312篇
  2010年   131546篇
  2009年   131483篇
  2008年   140297篇
  2007年   150778篇
  2006年   157864篇
  2005年   153110篇
  2004年   153193篇
  2003年   142988篇
  2002年   133293篇
  2001年   206828篇
  2000年   204884篇
  1999年   183910篇
  1998年   77253篇
  1997年   71769篇
  1996年   69771篇
  1995年   65396篇
  1994年   59507篇
  1993年   55116篇
  1992年   139193篇
  1991年   134382篇
  1990年   129009篇
  1989年   125675篇
  1988年   116653篇
  1987年   114390篇
  1986年   108685篇
  1985年   105686篇
  1984年   85184篇
  1983年   75172篇
  1982年   54510篇
  1981年   50328篇
  1980年   47248篇
  1979年   77147篇
  1978年   59445篇
  1977年   52057篇
  1976年   48087篇
  1975年   49343篇
  1974年   57024篇
  1973年   54844篇
  1972年   51872篇
  1971年   48154篇
排序方式: 共有10000条查询结果,搜索用时 170 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