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   15090篇
  免费   1154篇
  国内免费   33篇
耳鼻咽喉   127篇
儿科学   599篇
妇产科学   266篇
基础医学   2097篇
口腔科学   274篇
临床医学   2220篇
内科学   2990篇
皮肤病学   202篇
神经病学   1539篇
特种医学   311篇
外科学   1503篇
综合类   314篇
一般理论   23篇
预防医学   1799篇
眼科学   173篇
药学   990篇
中国医学   37篇
肿瘤学   813篇
  2023年   102篇
  2022年   126篇
  2021年   281篇
  2020年   201篇
  2019年   285篇
  2018年   341篇
  2017年   266篇
  2016年   260篇
  2015年   311篇
  2014年   456篇
  2013年   695篇
  2012年   945篇
  2011年   1083篇
  2010年   610篇
  2009年   499篇
  2008年   955篇
  2007年   983篇
  2006年   937篇
  2005年   896篇
  2004年   854篇
  2003年   722篇
  2002年   730篇
  2001年   272篇
  2000年   261篇
  1999年   239篇
  1998年   170篇
  1997年   119篇
  1996年   122篇
  1995年   129篇
  1994年   127篇
  1993年   116篇
  1992年   163篇
  1991年   164篇
  1990年   134篇
  1989年   123篇
  1988年   119篇
  1987年   107篇
  1986年   110篇
  1985年   106篇
  1984年   81篇
  1983年   96篇
  1982年   94篇
  1981年   82篇
  1980年   62篇
  1979年   81篇
  1978年   85篇
  1977年   45篇
  1975年   52篇
  1974年   41篇
  1973年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
A convenience sample of hospital workers, those receiving influenza vaccine and those not receiving vaccine, were asked to complete questionnaires delineating the occurrence of symptoms (e.g., fever, headache, extreme tiredness, dry cough, sore throat, runny nose, stuffy nose, muscle aches) and absenteeism in the 7-day period post-vaccination if vaccinated. Those unvaccinated completed the questionnaire in a self-selected 7 consecutive day period during the study conducted from November 2004 to February 2005. Those receiving either Fluzone or FluMist reported significantly fewer symptoms and related absenteeism than the unvaccinated group (p < .05). Administration of influenza vaccine did not result in higher rates of post-vaccination symptoms as compared to an unvaccinated group. Further, vaccinated employees did not experience higher absenteeism rates as a result of receiving either influenza vaccine. However, for those reporting absenteeism as a result of symptoms, mean absenteeism days were highest in the FluMist group (4.5 days) compared to the unvaccinated group (2.1 days) and the Fluzone group (1.9 days).  相似文献   
12.
13.
BACKGROUND: Although nationally recognized learning objectives for undergraduate surgical education exist, the extent to which Canadian medical schools follow these guidelines has never been established. METHODS: We distributed a survey to all program directors and clinical-teaching-unit coordinators for undergraduate surgery at Canada's 16 medical schools, and subsequently assessed the perceived emphasis placed on learning objectives and student performance, and the impact of instructional tools and teaching locations. RESULTS: Program directors in 15 medical schools responded to the survey. We identified a wide variation in the emphasis placed on basic learning objectives as well as specialty specific learning objectives. The length of rotations, methods of instruction and tools used to grade student performance also varied widely. CONCLUSIONS: Our findings suggest significant variation in the design and implementation of undergraduate surgical education in Canada. This study may serve as a basis for reassessing learning objectives in Canadian undergraduate surgical education.  相似文献   
14.
15.
A serotonin (5-HT)-mediated phosphoinositide hydrolysis response was characterized in fibroblasts cultured from rabbit choroid plexus. 5-HT elicited a maximum 8-fold increase in [3H]inositol-phosphate ([3H]IP) formation, while the partial agonists, (+)-lysergic acid diethylamide and (−)-1-(4-bromo-2,5-dimethyoxyphenyl)-2-aminopropane caused 2- and 5-fold increases, respectively. Mianserin, ketanserin, and spiperone were equipotent at blocking the 5-HT-mediated response. Thus, agonist and antagonist profiles indicate interactions with 5-HT2 receptors.  相似文献   
16.
17.
18.
We tested the hypothesis that since the implementation of the prospective payment system (PPS), elderly patients hospitalized for hip fractures receive shorter, less care-intensive hospitalizations and are more frequently institutionalized. In blinded fashion, we reviewed the charts of elderly patients with hip fractures admitted to a municipal hospital from 1981 through 1985. Demographic and clinical characteristics of patients treated before implementation of the PPS were similar to patients treated thereafter. After implementation of the PPS, the mean length of hospitalization fell from 16.6 to 10.3 days, and the mean number of physical therapy sessions received decreased from 9.7 to 4.9. Concomitantly, the proportion of patients discharged to a nursing home increased (21% to 48%), as did the proportion receiving nursing home care at six months after discharge (13% to 39%). This increase in long-term nursing home placement suggests that the quality of care for elderly patients with hip fractures may have deteriorated.  相似文献   
19.
20.
The Child and Adolescent Trial for Cardiovascular Health (CATCH) is a multisite intervention research study that builds on significant progress made in school health education research in the 1980s. The study has three phases: Phase I deals with study design, intervention, and measurement development, Phase II involves the main trial in 96 schools in four states, and Phase III focuses on analysis. The intervention program targets third-fifth grade students and focuses on multiple cardiovascular health behaviors, including eating habits, physical activity, and cigarette smoking. Classroom curricula, school environmental change, and family involvement programs are developed for each grade level and behavioral focus. This paper describes Phase II of CATCH with a rationale for cardiovascular health promotion with youth. The process of change that appears to be necessary for school-based health promotion and that will be tested in CATCH are presented as a framework to guide these efforts.  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