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   2734427篇
  免费   201702篇
  国内免费   7257篇
耳鼻咽喉   35958篇
儿科学   89840篇
妇产科学   74402篇
基础医学   393602篇
口腔科学   78536篇
临床医学   255471篇
内科学   527387篇
皮肤病学   59251篇
神经病学   219976篇
特种医学   101882篇
外国民族医学   592篇
外科学   400233篇
综合类   61697篇
现状与发展   5篇
一般理论   976篇
预防医学   216652篇
眼科学   63594篇
药学   201195篇
  12篇
中国医学   6791篇
肿瘤学   155334篇
  2021年   21331篇
  2019年   22435篇
  2018年   32527篇
  2017年   24700篇
  2016年   27283篇
  2015年   30721篇
  2014年   42413篇
  2013年   64004篇
  2012年   88092篇
  2011年   93411篇
  2010年   54893篇
  2009年   50545篇
  2008年   86414篇
  2007年   91683篇
  2006年   92080篇
  2005年   88369篇
  2004年   84766篇
  2003年   80831篇
  2002年   78272篇
  2001年   132624篇
  2000年   136351篇
  1999年   113110篇
  1998年   31053篇
  1997年   27411篇
  1996年   27239篇
  1995年   26032篇
  1994年   24144篇
  1993年   22417篇
  1992年   86955篇
  1991年   84358篇
  1990年   81277篇
  1989年   77875篇
  1988年   71447篇
  1987年   69825篇
  1986年   66205篇
  1985年   63055篇
  1984年   46943篇
  1983年   39989篇
  1982年   23217篇
  1979年   41987篇
  1978年   29455篇
  1977年   24683篇
  1976年   23485篇
  1975年   24429篇
  1974年   29687篇
  1973年   28836篇
  1972年   26691篇
  1971年   24765篇
  1970年   23030篇
  1969年   21344篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
51.
52.
53.
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   
54.
55.
56.
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   
57.
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   
58.
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   
59.
60.
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