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   1029685篇
  免费   103255篇
  国内免费   4184篇
耳鼻咽喉   17853篇
儿科学   30249篇
妇产科学   27847篇
基础医学   132826篇
口腔科学   27598篇
临床医学   102567篇
内科学   213663篇
皮肤病学   25032篇
神经病学   86862篇
特种医学   42385篇
外国民族医学   171篇
外科学   178360篇
综合类   24972篇
现状与发展   74篇
一般理论   277篇
预防医学   74991篇
眼科学   24277篇
药学   67709篇
中国医学   1620篇
肿瘤学   57791篇
  2020年   9071篇
  2018年   14677篇
  2017年   12973篇
  2016年   14827篇
  2015年   16114篇
  2014年   26300篇
  2013年   32387篇
  2012年   29164篇
  2011年   30373篇
  2010年   24553篇
  2009年   27397篇
  2008年   29629篇
  2007年   30014篇
  2006年   32167篇
  2005年   29323篇
  2004年   28081篇
  2003年   26277篇
  2002年   25490篇
  2001年   39697篇
  2000年   39563篇
  1999年   34255篇
  1998年   13023篇
  1997年   12106篇
  1996年   11898篇
  1995年   11260篇
  1994年   9775篇
  1993年   8894篇
  1992年   28132篇
  1991年   27572篇
  1990年   26770篇
  1989年   25902篇
  1988年   24298篇
  1987年   23790篇
  1986年   22664篇
  1985年   21896篇
  1984年   17050篇
  1983年   14612篇
  1982年   9492篇
  1979年   17101篇
  1978年   12532篇
  1977年   10650篇
  1976年   9664篇
  1975年   10477篇
  1974年   12930篇
  1973年   12428篇
  1972年   11887篇
  1971年   10916篇
  1970年   10490篇
  1969年   10038篇
  1968年   8949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