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   2143957篇
  免费   165508篇
  国内免费   3566篇
耳鼻咽喉   29131篇
儿科学   70663篇
妇产科学   59777篇
基础医学   313165篇
口腔科学   63131篇
临床医学   190231篇
内科学   413797篇
皮肤病学   46630篇
神经病学   167333篇
特种医学   84118篇
外国民族医学   534篇
外科学   323693篇
综合类   51091篇
现状与发展   4篇
一般理论   689篇
预防医学   163115篇
眼科学   49497篇
药学   163029篇
  5篇
中国医学   4862篇
肿瘤学   118536篇
  2018年   20841篇
  2016年   18150篇
  2015年   20738篇
  2014年   28409篇
  2013年   43080篇
  2012年   58344篇
  2011年   61581篇
  2010年   36400篇
  2009年   34597篇
  2008年   58500篇
  2007年   61918篇
  2006年   63061篇
  2005年   60647篇
  2004年   59715篇
  2003年   56787篇
  2002年   55687篇
  2001年   101780篇
  2000年   104919篇
  1999年   88400篇
  1998年   23732篇
  1997年   21233篇
  1996年   21366篇
  1995年   20796篇
  1994年   19476篇
  1993年   18219篇
  1992年   72236篇
  1991年   70768篇
  1990年   69106篇
  1989年   67225篇
  1988年   62286篇
  1987年   61001篇
  1986年   58134篇
  1985年   55831篇
  1984年   41616篇
  1983年   35616篇
  1982年   20599篇
  1981年   18442篇
  1980年   17314篇
  1979年   39223篇
  1978年   27319篇
  1977年   23015篇
  1976年   21894篇
  1975年   23345篇
  1974年   28260篇
  1973年   27115篇
  1972年   25056篇
  1971年   23531篇
  1970年   21905篇
  1969年   20420篇
  1968年   18726篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
81.
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   
82.
83.
Molecular characterization of Wuchereria bancrofti is essential to develop suitable anti-filarial drugs and vaccines. We describe here isolation, sequence analysis and cloning of a partial cDNA of an enzyme superoxide dismutase from this parasite. The immunoscreening of a lambda zap W. bancrofti microfilarial (Mf) cDNA library with microfilaremic sera had resulted in the isolation of several seroreactive clones including, WbSOD. This clone contained a 309 bp insert and showed significant nucleotide and deduced amino acid sequence homologies to the superoxide dismutases of other nematode parasites. The antioxidant property of this enzyme may have important contribution in the defense mechanism of the parasite against host immune response.  相似文献   
84.
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   
85.
86.
Consecutive patients (n = 215) who were referred to optometric (55%) or multidisciplinary (45%) low-vision services and above 50 years of age were recruited from four hospitals in the Netherlands. They completed two vision-related quality of life questionnaires, the Vision Quality of Life Core Measure (VCM1) and the Low Vision Quality of Life Questionnaire (LVQOL), before their first visit with low-vision services and 1 year later. At follow-up, patients referred to multidisciplinary low-vision services had lower scores on the mobility subscale of the LVQOL than patients referred to optometric low-vision services [5.3 points; 95% confidence interval (CI): 0.2-10.5]. Paired sample t-tests for the two groups of patients taken together show improvement for the VCM1 (3.1 points; 95% CI: 0.6-5.6) and deterioration for the basic aspects of vision (3.5 points; 95% CI: 1.1-5.9) and the mobility (6.6 points; 95% CI: 3.7-9.5) subscales of the LVQOL. In conclusion, people referred to optometric services showed less deterioration in mobility than those referred to multidisciplinary services. No differences were observed for any of the other subscales of the LVQOL and the VCM1. Future research in this field should include randomized controlled designs comparing low-vision services with no treatment or placebo.  相似文献   
87.
88.
89.
Research coordinators in intensive care are a growing specialty about which little is known. This cross-sectional study surveyed the Australia and New Zealand Intensive Care Research Coordinators' Group (n = 49) regarding demographics, education, employment history, job structure, and role content. Most research coordinators were highly qualified and experienced nurses who undertake pharmaceutical trials, multicenter projects, departmental medical and nursing research, audits and data registries, and their own projects.  相似文献   
90.
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