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   948059篇
  免费   99742篇
  国内免费   2814篇
耳鼻咽喉   14977篇
儿科学   27050篇
妇产科学   27363篇
基础医学   126150篇
口腔科学   30289篇
临床医学   99652篇
内科学   186251篇
皮肤病学   20117篇
神经病学   81280篇
特种医学   38443篇
外国民族医学   171篇
外科学   152102篇
综合类   24722篇
现状与发展   42篇
一般理论   265篇
预防医学   79148篇
眼科学   22492篇
药学   65493篇
中国医学   1601篇
肿瘤学   53007篇
  2018年   13710篇
  2017年   12635篇
  2016年   13879篇
  2015年   15167篇
  2014年   20764篇
  2013年   27900篇
  2012年   25910篇
  2011年   26802篇
  2010年   20025篇
  2009年   21424篇
  2008年   25592篇
  2007年   26638篇
  2006年   27624篇
  2005年   25935篇
  2004年   24891篇
  2003年   23785篇
  2002年   22797篇
  2001年   37542篇
  2000年   37569篇
  1999年   32489篇
  1998年   11125篇
  1997年   10281篇
  1996年   10273篇
  1995年   9528篇
  1994年   8727篇
  1992年   27352篇
  1991年   26695篇
  1990年   26105篇
  1989年   25166篇
  1988年   23706篇
  1987年   23255篇
  1986年   22078篇
  1985年   21383篇
  1984年   16624篇
  1983年   14284篇
  1982年   9067篇
  1981年   8394篇
  1979年   16812篇
  1978年   12234篇
  1977年   10297篇
  1976年   9426篇
  1975年   10222篇
  1974年   12721篇
  1973年   12197篇
  1972年   11606篇
  1971年   10735篇
  1970年   10286篇
  1969年   9938篇
  1968年   8915篇
  1967年   8239篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.

Objective

The aim of the study was to estimate the effect of the state-based reinsurance programs through the section 1332 State Innovation Waivers on health insurance marketplace premiums and insurer participation.

Data Source

2015 to 2022 Robert Wood Johnson Foundation Health Insurance Exchange Compare Datasets.

Study Design

An event study difference-in-differences (DD) model separately for each year of implementation and a synthetic control method (SCM) are used to estimate year-by-year effects following program implementation.

Data Collection/Extraction Methods

Not applicable.

Principal Findings

Reinsurance programs were associated with a decline in premiums in the first year of implementation by 10%–13%, 5%–19%, and 11%–17% for bronze, silver, and gold plans (p < 0.05). There is a trend of sustained declines especially for states that implemented their programs in 2019 and 2020. The SCM analyses suggest some effect heterogeneity across states but also premium declines across most states. There is no evidence that reinsurance programs affected insurer participation.

Conclusion

State-based reinsurance programs have the potential to improve the affordability of health insurance coverage. However, reinsurance programs do not appear to have had an effect on insurer participation, highlighting the need for policy makers to consider complementary strategies to encourage insurer participation.  相似文献   
2.
3.

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   
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