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   245708篇
  免费   36312篇
  国内免费   2732篇
耳鼻咽喉   6103篇
儿科学   7719篇
妇产科学   4087篇
基础医学   15296篇
口腔科学   3186篇
临床医学   36469篇
内科学   65816篇
皮肤病学   8632篇
神经病学   24267篇
特种医学   10018篇
外国民族医学   3篇
外科学   55912篇
综合类   1307篇
现状与发展   72篇
一般理论   131篇
预防医学   14933篇
眼科学   5322篇
药学   7312篇
中国医学   114篇
肿瘤学   18053篇
  2024年   731篇
  2023年   5209篇
  2022年   2051篇
  2021年   5029篇
  2020年   7158篇
  2019年   4136篇
  2018年   9682篇
  2017年   8895篇
  2016年   10093篇
  2015年   10399篇
  2014年   18501篇
  2013年   19834篇
  2012年   12749篇
  2011年   13144篇
  2010年   14559篇
  2009年   17900篇
  2008年   12620篇
  2007年   11223篇
  2006年   13393篇
  2005年   10420篇
  2004年   9564篇
  2003年   7888篇
  2002年   7649篇
  2001年   4508篇
  2000年   3458篇
  1999年   3986篇
  1998年   4724篇
  1997年   4256篇
  1996年   3997篇
  1995年   3791篇
  1994年   2471篇
  1993年   2098篇
  1992年   1767篇
  1991年   1751篇
  1990年   1349篇
  1989年   1434篇
  1988年   1261篇
  1987年   1115篇
  1986年   1098篇
  1985年   978篇
  1984年   830篇
  1983年   764篇
  1982年   838篇
  1981年   674篇
  1980年   575篇
  1979年   396篇
  1978年   453篇
  1977年   498篇
  1975年   341篇
  1972年   346篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
11.
12.
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   
13.
14.
15.
CONTEXT: The physician assistant profession has been moving toward requiring master's degrees for new practitioners, but some argue this could change the face of the discipline. PURPOSE: To see if there is an association between physician assistants' academic degrees and practice in primary care, in rural areas, and with the medically underserved. METHODS: Surveys were sent to 880 graduates of the first 32 University of Washington physician assistant classes through 2000. Respondents noted their academic degree at program entry and the highest degree attained at any time up to the time of survey. Relationships between practice characteristics and academic degree levels were tested by unadjusted odds ratios and logistic regression after controlling for year of graduation and sex. RESULTS: Of the 478 respondents, 54% worked in primary care, about 30% practiced in nonmetropolitan communities, and 42% reported providing care for the medically underserved. Respondents with no degree (33% of total at entry, 24% at survey) were significantly more likely than degree holders to work in primary care and nonmetropolitan areas. Respondents with no degree at program entry were significantly more likely, and those with no degree at the time of the survey were marginally more likely, to self-report work with the medically underserved. CONCLUSION: Respondents with no academic degree are significantly more likely to demonstrate a commitment to primary, rural, and underserved health care. These findings may inform the national debate about the impact of required advanced degrees on the practice patterns of nonphysician providers.  相似文献   
16.
17.
18.
19.
20.
The prevalence of heavy alcohol consumption is a major problem of increasing proportions throughout the world. Although alcohol sensitizing drugs and more recently serotonin uptake inhibitors are drug interventions with some following, their long term beneficial consequences have yet to be demonstrated. In recent years, we have demonstrated that manipulating activity in the renin-angiotensin system will dramatically alter voluntary alcohol consumption in rats. Based on these findings, the present study evaluated the ability of a class of drugs known as the angiotensin converting enzyme inhibitors to reduce voluntary alcohol drinking in laboratory animals. These drugs prevent the conversion of angiotensin I to angiotensin II. They have been licensed for use in Europe and North America and are indicated in the treatment of hypertension. Our experiments showed that both captopril (Capoten, Squibb) and enalapril (Vasotec, Merck Sharpe & Dohme) can reduce alcohol drinking in both normotensive and hypertensive animals regardless of whether the pattern of intake is in a bout or of a less exaggerated nature. Furthermore, this change in alcohol intake can occur without concomitant changes in blood pressure, plasma renin activity, overall fluid balance, or the distribution and metabolism of alcohol. Taken together these findings suggest that the angiotensin converting enzyme inhibitors should be evaluated in a clinical setting for they may prove to be a useful new treatment or treatment adjunct for alcohol abuse in humans.  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