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   3269039篇
  免费   232818篇
  国内免费   6188篇
耳鼻咽喉   48337篇
儿科学   99994篇
妇产科学   89040篇
基础医学   454612篇
口腔科学   96177篇
临床医学   291339篇
内科学   632428篇
皮肤病学   68799篇
神经病学   269592篇
特种医学   129258篇
外国民族医学   1251篇
外科学   494754篇
综合类   78207篇
现状与发展   7篇
一般理论   1307篇
预防医学   252862篇
眼科学   78280篇
药学   244224篇
  69篇
中国医学   6368篇
肿瘤学   171140篇
  2018年   31743篇
  2016年   27380篇
  2015年   30736篇
  2014年   44141篇
  2013年   67419篇
  2012年   89972篇
  2011年   95085篇
  2010年   56111篇
  2009年   54180篇
  2008年   90755篇
  2007年   97285篇
  2006年   98227篇
  2005年   95846篇
  2004年   92397篇
  2003年   89537篇
  2002年   88440篇
  2001年   149457篇
  2000年   154538篇
  1999年   131053篇
  1998年   37285篇
  1997年   33994篇
  1996年   33158篇
  1995年   32042篇
  1994年   30021篇
  1993年   27939篇
  1992年   104856篇
  1991年   101214篇
  1990年   98242篇
  1989年   95096篇
  1988年   88346篇
  1987年   87071篇
  1986年   82942篇
  1985年   79230篇
  1984年   59894篇
  1983年   51038篇
  1982年   31008篇
  1981年   27778篇
  1980年   26032篇
  1979年   56767篇
  1978年   40162篇
  1977年   34345篇
  1976年   31746篇
  1975年   34472篇
  1974年   41888篇
  1973年   40144篇
  1972年   37984篇
  1971年   35387篇
  1970年   33421篇
  1969年   31357篇
  1968年   28854篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
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   
102.
103.
Severe adverse effects during the use of ovulation inhibitors occur mostly in women who have an elevated risk for the development of certain diseases owing to hereditary or acquired factors. By means of a careful personal or family history analysis as well as specific laboratory examinations, an existing predisposition may frequently be diagnosed and the individual risk associated with the use of oral contraceptive inhibitors may be estimated. The present contribution describes the potential effects of treatment with ovulation inhibitors on women with thrombophilia, cardiovascular disease, diabetes mellitus, dyslipidemia, overweight or underweight, tumors, psychiatric and neurological diseases and autoimmune disease. The hormonal methods and non-hormonal alternatives available for contraception are elucidated according to existing lesions and risk factors and the advantages and disadvantages are discussed.  相似文献   
104.
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   
105.
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   
106.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  相似文献   
107.
108.
109.
110.
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