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   3252217篇
  免费   250544篇
  国内免费   6929篇
耳鼻咽喉   47530篇
儿科学   102925篇
妇产科学   89880篇
基础医学   462380篇
口腔科学   93307篇
临床医学   292285篇
内科学   630235篇
皮肤病学   67172篇
神经病学   266937篇
特种医学   128973篇
外国民族医学   1183篇
外科学   492933篇
综合类   77804篇
现状与发展   6篇
一般理论   1211篇
预防医学   256628篇
眼科学   76877篇
药学   245067篇
  24篇
中国医学   7061篇
肿瘤学   169272篇
  2018年   32888篇
  2016年   28023篇
  2015年   31975篇
  2014年   45429篇
  2013年   68728篇
  2012年   93270篇
  2011年   98780篇
  2010年   58138篇
  2009年   55280篇
  2008年   93598篇
  2007年   100316篇
  2006年   101471篇
  2005年   99111篇
  2004年   95211篇
  2003年   91751篇
  2002年   90697篇
  2001年   146715篇
  2000年   151642篇
  1999年   128573篇
  1998年   37622篇
  1997年   33879篇
  1996年   33746篇
  1995年   32521篇
  1994年   30561篇
  1993年   28367篇
  1992年   103779篇
  1991年   100990篇
  1990年   98277篇
  1989年   94958篇
  1988年   88221篇
  1987年   86772篇
  1986年   82443篇
  1985年   78923篇
  1984年   59666篇
  1983年   51096篇
  1982年   30978篇
  1981年   27559篇
  1980年   25821篇
  1979年   56300篇
  1978年   39799篇
  1977年   33715篇
  1976年   31882篇
  1975年   34069篇
  1974年   41468篇
  1973年   39511篇
  1972年   37351篇
  1971年   34570篇
  1970年   32463篇
  1969年   30477篇
  1968年   28200篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
灾难的时代错误:灾害医学的过去、现在和将来(一)   总被引:1,自引:0,他引:1  
灾难,特别是地震、火山、洪水以及与战争有关的事件如饥饿和流行性传染病,是人类有记录的经历的一部分。从意大利庞贝的火山爆发,到约翰斯顿的洪水、第二次世界大战和黑色瘟疫,到西班牙流感,都发生了灾难,这不会被传说和历史书籍长期忘却。不过,在20世纪中叶以前,那些灾难的发生相对较少,且相距时间较长。从20世纪中叶以来,灾难的本质发生了变化。从恐怖分子使用“新技术”,到与气候有关的导致亿万美元经济损失的事件,表明这个世界正在发生变化。仅仅在最近的50~60年间,造成多种多样的伤亡事件,其危险性和频率的增加引人注目,并且注定要在接…  相似文献   
102.
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction.  相似文献   
103.
104.
105.
106.
107.
High levels of tumor necrosis factor-alpha (TNF-alpha), a pro-inflammatory cytokine, are present in the wound fluid of chronic nonhealing wounds. This leads to increased inflammation, cytokine expression, and ultimately results in impaired wound healing and tissue destruction. Etanercept is a recombinant fusion protein that consists of the soluble TNF receptor (p75) linked to the Fc portion of human IgG1. It is an effective inhibitor of TNF-alpha and has been shown to provide rapid and sustained improvement in rheumatoid arthritis by acting as a soluble receptor binding TNF-alpha and preventing its proinflammatory activities. Therefore, the aim of this study was to determine whether Etanercept could inhibit TNF-alpha activity in chronic wound fluid. Wound fluid was collected from the venous leg ulcers of 16 different patients. The effect of Etanercept on TNF-alpha activity was evaluated using both a TNF-alpha bioassay and an enzyme-linked immunoassay. Etanercept was found to reduce the cytotoxic effect of chronic wound fluid on L929 fibroblasts by approximately 30% and neutralized TNF-alpha binding in the enzyme-linked immunoassay by up to 80%. Direct application of Etanercept to chronic wounds may therefore reduce the inflammatory activity of TNF-alpha, which could reduce the chronicity of venous leg ulcers and thus aid in the healing of these wounds.  相似文献   
108.
109.
For many parents stopping life-sustaining medical treatment on their dying infant is psychologically impossible. Dostoevsky's insights into human behavior, particularly the fact that individuals do not want the anxiety and guilt associated with responsibility for making difficult decisions, might change the way physicians approach parents for permission to withdraw life-prolonging medical interventions on dying infants.  相似文献   
110.
The authors discuss techniques for Monte Carlo (MC) cohort simulations that reduce the number of simulation replications required to achieve a given degree of precision for various output measures. Known as variance reduction techniques, they are often used in industrial engineering and operations research models, but they are seldom used in medical models. However, most MC cohort simulations are well suited to the implementation of these techniques. The authors discuss the cost of implementation versus the benefit of reduced replications.  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