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   2500941篇
  免费   231467篇
  国内免费   12620篇
耳鼻咽喉   34277篇
儿科学   78665篇
妇产科学   62425篇
基础医学   424778篇
口腔科学   66149篇
临床医学   224262篇
内科学   420663篇
皮肤病学   74877篇
神经病学   223001篇
特种医学   99156篇
外国民族医学   26篇
外科学   397557篇
综合类   81802篇
现状与发展   23篇
一般理论   2000篇
预防医学   215944篇
眼科学   55971篇
药学   166933篇
  22篇
中国医学   7753篇
肿瘤学   108744篇
  2022年   22495篇
  2021年   54084篇
  2020年   34546篇
  2019年   57394篇
  2018年   68635篇
  2017年   52171篇
  2016年   57428篇
  2015年   72347篇
  2014年   106297篇
  2013年   171179篇
  2012年   65667篇
  2011年   61288篇
  2010年   108884篇
  2009年   115707篇
  2008年   49065篇
  2007年   48351篇
  2006年   60835篇
  2005年   56640篇
  2004年   59200篇
  2003年   50829篇
  2002年   40974篇
  2001年   52115篇
  2000年   43158篇
  1999年   53652篇
  1998年   59746篇
  1997年   59117篇
  1996年   56710篇
  1995年   52319篇
  1994年   46477篇
  1993年   43601篇
  1992年   34465篇
  1991年   32102篇
  1990年   29509篇
  1989年   30096篇
  1988年   28178篇
  1987年   27439篇
  1986年   26142篇
  1985年   27655篇
  1984年   30715篇
  1983年   29707篇
  1982年   35615篇
  1981年   34134篇
  1980年   32270篇
  1979年   22976篇
  1978年   24452篇
  1977年   23548篇
  1976年   21299篇
  1975年   18806篇
  1974年   17302篇
  1973年   16547篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
131.
132.
133.
134.
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   
135.
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   
136.
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   
137.
138.
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   
139.
Abstract

Objective: This study aims at identifying associations between cognitive function and suicidal ideation in the sample of patients with anxiety and mood disorders (AMD).

Methods: In sum, 186 (age = 39?±?12.3 years; 142 [76.3%] females) patients with AMD were enrolled in the study. Assessment included evaluation of socio-demographic information, medication use, anxiety and depression symptoms. Cognitive tests included measures of psychomotor performance and incidental learning using the Digit Symbol Test. Trail Making Tests respectively measured perceptual speed, task-switching and executive control. Additionally, 21 patients completed tests from the Cambridge Automated Neuropsychological Test Battery measuring set shifting (Interdimensional/extradimensional set-shift), executive planning (Stockings of Cambridge), and decision making (Cambridge Gamble Task [CGT]).

Results: Almost half (45.0%, n?=?86) of the study sample patients had experienced suicidal ideations. In multivariable regression analysis, suicidal ideation was associated with a greater overall proportion of bet and risk taking on the CGT task (β?=?0.726, p?=?.010 and β?=?0.634, p?=?.019), when controlling for socio-demographic characteristics, medication use, anxiety and depression symptoms.

Conclusions: Outpatients with AMD and suicidal ideation could be distinguished by the presence of cognitive deficits in the executive function domain, particularly in impulse-control and risk taking.  相似文献   
140.
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