首页 | 官方网站   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   539157篇
  免费   57392篇
  国内免费   5192篇
医药卫生   601741篇
  2023年   5358篇
  2021年   5821篇
  2020年   7596篇
  2019年   5054篇
  2018年   11939篇
  2017年   10811篇
  2016年   12006篇
  2015年   12490篇
  2014年   21157篇
  2013年   23251篇
  2012年   16163篇
  2011年   16362篇
  2010年   16895篇
  2009年   20369篇
  2008年   15942篇
  2007年   15120篇
  2006年   17468篇
  2005年   13889篇
  2004年   12498篇
  2003年   11230篇
  2002年   10985篇
  2001年   32148篇
  2000年   31868篇
  1999年   26981篇
  1998年   8918篇
  1997年   7787篇
  1996年   7260篇
  1995年   6737篇
  1994年   5115篇
  1993年   4479篇
  1992年   17445篇
  1991年   16271篇
  1990年   15256篇
  1989年   15159篇
  1988年   13632篇
  1987年   12925篇
  1986年   12025篇
  1985年   11083篇
  1984年   7517篇
  1983年   6168篇
  1982年   3303篇
  1979年   5823篇
  1978年   3708篇
  1977年   3413篇
  1975年   2943篇
  1974年   3328篇
  1973年   3130篇
  1972年   3137篇
  1971年   3007篇
  1970年   2800篇
排序方式: 共有10000条查询结果,搜索用时 125 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.
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   
10.
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-23

京公网安备 11010802026262号