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   1842553篇
  免费   132491篇
  国内免费   4079篇
耳鼻咽喉   24433篇
儿科学   61038篇
妇产科学   49979篇
基础医学   263616篇
口腔科学   53174篇
临床医学   162635篇
内科学   360042篇
皮肤病学   42879篇
神经病学   145381篇
特种医学   71647篇
外国民族医学   267篇
外科学   281140篇
综合类   39842篇
现状与发展   4篇
一般理论   564篇
预防医学   131287篇
眼科学   44057篇
药学   134216篇
  7篇
中国医学   4773篇
肿瘤学   108142篇
  2021年   14056篇
  2019年   14803篇
  2018年   22432篇
  2017年   17253篇
  2016年   19423篇
  2015年   22130篇
  2014年   29608篇
  2013年   42711篇
  2012年   59974篇
  2011年   62312篇
  2010年   36905篇
  2009年   34166篇
  2008年   58291篇
  2007年   62310篇
  2006年   62805篇
  2005年   60439篇
  2004年   58204篇
  2003年   55621篇
  2002年   53708篇
  2001年   96350篇
  2000年   98198篇
  1999年   81136篇
  1998年   21198篇
  1997年   18491篇
  1996年   18289篇
  1995年   17532篇
  1994年   16033篇
  1993年   14742篇
  1992年   59443篇
  1991年   57311篇
  1990年   55022篇
  1989年   52664篇
  1988年   47830篇
  1987年   46610篇
  1986年   43830篇
  1985年   41519篇
  1984年   30589篇
  1983年   25923篇
  1982年   14593篇
  1979年   26841篇
  1978年   18561篇
  1977年   15743篇
  1976年   14572篇
  1975年   15591篇
  1974年   18686篇
  1973年   17906篇
  1972年   16633篇
  1971年   15404篇
  1970年   14258篇
  1969年   13303篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
22.
23.
24.
25.
26.
27.
Graefe's Archive for Clinical and Experimental Ophthalmology - The published online version contains mistake as the author's first name and last name have been interchanged as "Hild...  相似文献   
28.
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   
29.
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   
30.
Monitoring variations in the functioning of the autonomic nervous system may help personalize training of runners and provide more pronounced physiological adaptations and performance improvements. We systematically reviewed the scientific literature comparing physiological adaptations and/or improvements in performance following training based on responses of the autonomic nervous system (ie, changes in heart rate variability) and predefined training. PubMed, SPORTDiscus, and Web of Science were searched systematically in July 2019. Keywords related to endurance, running, autonomic nervous system, and training. Studies were included if they (a) involved interventions consisting predominantly of running training; (b) lasted at least 3 weeks; (c) reported pre- and post-intervention assessment of running performance and/or physiological parameters; (d) included an experimental group performing training adjusted continuously on the basis of alterations in HRV and a control group; and (e) involved healthy runners. Five studies involving six interventions and 166 participants fulfilled our inclusion criteria. Four HRV-based interventions reduced the amount of moderate- and/or high-intensity training significantly. In five interventions, improvements in performance parameters (3000 m, 5000 m, Loadmax, Tlim) were more pronounced following HRV-based training. Peak oxygen uptake () and submaximal running parameters (eg, LT1, LT2) improved following both HRV-based and predefined training, with no clear difference in the extent of improvement in . Submaximal running parameters tended to improve more following HRV-based training. Research findings to date have been limited and inconsistent. Both HRV-based and predefined training improve running performance and certain submaximal physiological adaptations, with effects of the former training tending to be greater.  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