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   1221084篇
  免费   116723篇
  国内免费   4917篇
耳鼻咽喉   19616篇
儿科学   35537篇
妇产科学   31787篇
基础医学   156849篇
口腔科学   31005篇
临床医学   122314篇
内科学   253224篇
皮肤病学   27208篇
神经病学   105472篇
特种医学   48540篇
外国民族医学   182篇
外科学   206284篇
综合类   28220篇
现状与发展   74篇
一般理论   571篇
预防医学   93093篇
眼科学   29395篇
药学   81308篇
  6篇
中国医学   1930篇
肿瘤学   70109篇
  2021年   12460篇
  2020年   11434篇
  2019年   11875篇
  2018年   19236篇
  2017年   16293篇
  2016年   18321篇
  2015年   20433篇
  2014年   32619篇
  2013年   41262篇
  2012年   43707篇
  2011年   45589篇
  2010年   32570篇
  2009年   34105篇
  2008年   42680篇
  2007年   43780篇
  2006年   45772篇
  2005年   42867篇
  2004年   40790篇
  2003年   38065篇
  2002年   36393篇
  2001年   41360篇
  2000年   40862篇
  1999年   35959篇
  1998年   15146篇
  1997年   13856篇
  1996年   13368篇
  1995年   12687篇
  1994年   11030篇
  1992年   29144篇
  1991年   28511篇
  1990年   27613篇
  1989年   26723篇
  1988年   25105篇
  1987年   24599篇
  1986年   23496篇
  1985年   22744篇
  1984年   18056篇
  1983年   15527篇
  1982年   10563篇
  1979年   17713篇
  1978年   13109篇
  1977年   11137篇
  1976年   10124篇
  1975年   10833篇
  1974年   13324篇
  1973年   12762篇
  1972年   12158篇
  1971年   11161篇
  1970年   10707篇
  1969年   10178篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.

Physical activity brings significant health benefits to middle-aged adults, although the research to date has been focused on late adulthood. This study aims to examine how ageing affects the self-reported and accelerometer-derived measures of physical activity levels in middle-aged adults. We employed the data recorded in the UK Biobank and analysed the physical activity levels of 2,998 participants (1381 men and 1617 women), based on self-completion questionnaire and accelerometry measurement of physical activity. We also assessed the musculoskeletal health of the participants using the dual-energy X-ray absorptiometry (DXA) measurements provided by the UK Biobank. Participants were categorised into three groups according to their age: group I younger middle-aged (40 to 49 years), group II older middle-aged (50 to 59 years), and group III oldest middle-aged (60 to 69 years). Self-reported physical activity level increased with age and was the highest in group III, followed by group II and I (P?<?0.05). On the contrary, physical activity measured by accelerometry decreased significantly with age from group I to III (P?<?0.05), and the same pertained to the measurements of musculoskeletal health (P?<?0.05). It was also shown that middle-aged adults mostly engaged in low and moderate intensity activities. The opposing trends of the self-reported and measured physical activity levels may suggest that middle-aged adults over-report their activity level as they age. They should be aware of the difference between their perceived and actual physical activity levels, and objective measures would be useful to prevent the decline in musculoskeletal health.

  相似文献   
3.
4.
5.
6.
7.
8.
9.
10.
PurposeUnderstanding the value of genetic screening and testing for monogenic disorders requires high-quality, methodologically robust economic evaluations. This systematic review sought to assess the methodological quality among such studies and examined opportunities for improvement.MethodsWe searched PubMed, Cochrane, Embase, and Web of Science for economic evaluations of genetic screening/testing (2013-2019). Methodological rigor and adherence to best practices were systematically assessed using the British Medical Journal checklist.ResultsAcross the 47 identified studies, there were substantial variations in modeling approaches, reporting detail, and sophistication. Models ranged from simple decision trees to individual-level microsimulations that compared between 2 and >20 alternative interventions. Many studies failed to report sufficient detail to enable replication or did not justify modeling assumptions, especially for costing methods and utility values. Meta-analyses, systematic reviews, or calibration were rarely used to derive parameter estimates. Nearly all studies conducted some sensitivity analysis, and more sophisticated studies implemented probabilistic sensitivity/uncertainty analysis, threshold analysis, and value of information analysis.ConclusionWe describe a heterogeneous body of work and present recommendations and exemplar studies across the methodological domains of (1) perspective, scope, and parameter selection; (2) use of uncertainty/sensitivity analyses; and (3) reporting transparency for improvement in the economic evaluation of genetic screening/testing.  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