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   2427748篇
  免费   197931篇
  国内免费   4337篇
耳鼻咽喉   34987篇
儿科学   73884篇
妇产科学   64050篇
基础医学   341885篇
口腔科学   69815篇
临床医学   219667篇
内科学   481438篇
皮肤病学   49260篇
神经病学   205514篇
特种医学   97066篇
外国民族医学   886篇
外科学   367647篇
综合类   56464篇
现状与发展   1篇
一般理论   998篇
预防医学   195270篇
眼科学   56501篇
药学   181021篇
  4篇
中国医学   4571篇
肿瘤学   129087篇
  2018年   25997篇
  2017年   19851篇
  2016年   21685篇
  2015年   25022篇
  2014年   35264篇
  2013年   53403篇
  2012年   73537篇
  2011年   76921篇
  2010年   44688篇
  2009年   42500篇
  2008年   72730篇
  2007年   77137篇
  2006年   78185篇
  2005年   75920篇
  2004年   72875篇
  2003年   70134篇
  2002年   69228篇
  2001年   113141篇
  2000年   117397篇
  1999年   98832篇
  1998年   28003篇
  1997年   25626篇
  1996年   25571篇
  1995年   24718篇
  1994年   23250篇
  1993年   21635篇
  1992年   79475篇
  1991年   76481篇
  1990年   73632篇
  1989年   70903篇
  1988年   65885篇
  1987年   64837篇
  1986年   61377篇
  1985年   58457篇
  1984年   44298篇
  1983年   37704篇
  1982年   22949篇
  1981年   20388篇
  1979年   41330篇
  1978年   29015篇
  1977年   24376篇
  1976年   22856篇
  1975年   23985篇
  1974年   29661篇
  1973年   28062篇
  1972年   26231篇
  1971年   24159篇
  1970年   22763篇
  1969年   21100篇
  1968年   19138篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel analysis among Swiss adolescents

Objective:  

To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels.  相似文献   
72.
73.
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   
74.
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   
75.
76.
77.
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   
78.
79.
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   
80.
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