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   1679908篇
  免费   120782篇
  国内免费   2530篇
耳鼻咽喉   23972篇
儿科学   55750篇
妇产科学   48700篇
基础医学   252280篇
口腔科学   47660篇
临床医学   143121篇
内科学   323837篇
皮肤病学   36427篇
神经病学   128285篇
特种医学   64651篇
外国民族医学   426篇
外科学   258287篇
综合类   33654篇
现状与发展   1篇
一般理论   407篇
预防医学   123894篇
眼科学   39112篇
药学   129231篇
  1篇
中国医学   3238篇
肿瘤学   90286篇
  2018年   15626篇
  2015年   15133篇
  2014年   20875篇
  2013年   31984篇
  2012年   43749篇
  2011年   47208篇
  2010年   27804篇
  2009年   26234篇
  2008年   45665篇
  2007年   49436篇
  2006年   50232篇
  2005年   49058篇
  2004年   47358篇
  2003年   45842篇
  2002年   45265篇
  2001年   76458篇
  2000年   78782篇
  1999年   66470篇
  1998年   18506篇
  1997年   16460篇
  1996年   16947篇
  1995年   15926篇
  1994年   15049篇
  1993年   14070篇
  1992年   53056篇
  1991年   52921篇
  1990年   52578篇
  1989年   50958篇
  1988年   47462篇
  1987年   46575篇
  1986年   44303篇
  1985年   42359篇
  1984年   31460篇
  1983年   27304篇
  1982年   15947篇
  1981年   14276篇
  1979年   30146篇
  1978年   21382篇
  1977年   18371篇
  1976年   17465篇
  1975年   19344篇
  1974年   22877篇
  1973年   21918篇
  1972年   20956篇
  1971年   19646篇
  1970年   18324篇
  1969年   17674篇
  1968年   16612篇
  1967年   14702篇
  1966年   13446篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
111.
112.
113.
114.
115.
116.
Graefe's Archive for Clinical and Experimental Ophthalmology - Retinal microvascular endothelial dysfunction is thought to be of importance in the development of ocular vascular diseases....  相似文献   
117.
118.
At this study a multi-criteria model was developed to examine the available procedures, techniques and methods of handling infectious waste in the large healthcare unit of University Regional General Hospital of Patras, Western Greece. Particularly, this study examined the: a) current legislation and Directives issued for medical waste management at Greece and among the other EU-members, b) contribution of healthcare wastes (HCW) generation rate on social and economic parameters in selected European countries, c) available procedures, techniques, and methods upon the disposal of infectious wastes at the healthcare studied, and, d) propositions for integrated management of such hazardous wastes. Specifically, the Analytic Hierarchy Process (AHP) methodology was applied under pair wise comparison matrices in two stages: 1) the scale factors and the indicators, and 2) the criteria and their sub–criteria. The assessment of these pair wise matrices included the indicators and the sub–criteria. Subsequently, two pair wise comparison matrices, upon a) the “Fulfillment of environmental objectives” indicator and b) the “Energy consumption” sub criterion, were denoted. The AHP methodology yielded good results; however there is still space of improving the environmental performance. The normalized relative weights obtained for the criteria and sub criteria motivated specific actions that have to be handled. Particularly, the results indicated a very good value in environmental management criteria due the values obtained for the commitment towards the environmental policy standards and the waste management procedures. However, further improvements on staff awareness (such as development programs to enhance sensitivity) and more green purchasing suppliers, should be further addressed.  相似文献   
119.
120.
Objective: Longitudinal data on cardiometabolic effects of egg intake during adolescence are lacking. The current analyses aim to evaluate the impact of usual adolescent egg consumption on lipid levels, fasting glucose, and insulin resistance during late adolescence (age 17–20?years).

Methods: Data from 1392 girls, aged 9 to 10 at baseline and followed for 10?years, in the National Heart, Lung, and Blood Institute’s National Growth and Health Study were used to examine the association between usual egg intake alone and in combination with other healthy lifestyle factors and late adolescent lipid levels, fasting glucose, and insulin resistance, measured as homeostasis model assessment of insulin resistance (HOMA-IR). Diet was assessed using 3-day food records during eight examination cycles. Girls were classified according to usual weekly egg intake, ages 9–17?years:?<1 egg/wk (n?=?361), 1 to <3 eggs/wk (n?=?703), and ≥3 eggs/wk (n?=?328). Analysis of covariance modeling was used to control for confounding by other behavioral and biological risk factors.

Results: Girls with low, moderate, and high egg intakes had adjusted low-density lipoprotein cholesterol levels of 99.7, 98.8, and 95.5 mg/dL, respectively (p?=?0.0778). In combination with higher intakes of fiber, dairy, or fruits and vegetables, these beneficial effects were stronger and statistically significant. There was no evidence that ≥3 eggs/wk had an adverse effect on lipids, glucose, or HOMA-IR. More active girls who consumed ≥3 eggs/wk had the lowest levels of insulin resistance.

Conclusion: These results suggest that eggs may be included as part of a healthy adolescent diet without adverse effects on glucose, lipid levels, or insulin resistance.  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