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   192887篇
  免费   67967篇
  国内免费   1139篇
耳鼻咽喉   3672篇
儿科学   7549篇
妇产科学   3426篇
基础医学   21499篇
口腔科学   9966篇
临床医学   40324篇
内科学   49574篇
皮肤病学   10445篇
神经病学   25996篇
特种医学   5863篇
外国民族医学   1篇
外科学   32708篇
综合类   459篇
现状与发展   40篇
一般理论   70篇
预防医学   20948篇
眼科学   3462篇
药学   8435篇
中国医学   1054篇
肿瘤学   16502篇
  2024年   555篇
  2023年   5219篇
  2022年   1418篇
  2021年   4619篇
  2020年   10714篇
  2019年   13389篇
  2018年   15848篇
  2017年   17329篇
  2016年   18336篇
  2015年   18405篇
  2014年   21179篇
  2013年   24138篇
  2012年   9661篇
  2011年   9668篇
  2010年   15852篇
  2009年   14632篇
  2008年   7455篇
  2007年   5489篇
  2006年   6692篇
  2005年   4998篇
  2004年   4225篇
  2003年   3671篇
  2002年   3614篇
  2001年   2722篇
  2000年   1942篇
  1999年   2124篇
  1998年   2444篇
  1997年   2180篇
  1996年   2167篇
  1995年   1864篇
  1994年   1271篇
  1993年   1096篇
  1992年   856篇
  1991年   728篇
  1990年   585篇
  1989年   598篇
  1988年   579篇
  1987年   443篇
  1986年   422篇
  1985年   362篇
  1984年   340篇
  1983年   368篇
  1982年   311篇
  1981年   294篇
  1980年   189篇
  1979年   105篇
  1978年   154篇
  1977年   156篇
  1976年   105篇
  1974年   86篇
排序方式: 共有10000条查询结果,搜索用时 312 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.
4.
5.
6.
7.
8.
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   
9.
10.
ObjectiveSpinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). We studied the effect of preimplantation opioid use on SCS outcome and the effect of SCS on opioid use during a two-year follow-up period.Materials and methodsThe study cohort included 211 consecutive FBSS patients who underwent an SCS trial from January 1997 to March 2014. Participants were divided into groups, which were as follows: 1) SCS trial only (n = 47), 2) successful SCS (implanted and in use throughout the two-year follow-up period, n = 131), and 3) unsuccessful SCS (implanted but later explanted or revised due to inadequate pain relief, n = 29). Patients who underwent explantation for other reasons (n = 4) were excluded. Opioid purchase data from January 1995 to March 2016 were retrieved from national registries.ResultsHigher preimplantation opioid doses associated with unsuccessful SCS (ROC: AUC = 0.66, p = 0.009), with 35 morphine milligram equivalents (MME)/day as the optimal cutoff value. All opioids were discontinued in 23% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.004). Strong opioids were discontinued in 39% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.04). Mean opioid dose escalated from 18 ± 4 MME/day to 36 ± 6 MME/day with successful SCS and from 22 ± 8 MME/day to 82 ± 21 MME/day with unsuccessful SCS (p < 0.001).ConclusionsHigher preimplantation opioid doses were associated with SCS failure, suggesting the need for opioid tapering before implantation. With continuous SCS therapy and no explantation or revision due to inadequate pain relief, 39% of FBSS patients discontinued strong opioids, and 23% discontinued all opioids. This indicates that SCS should be considered before detrimental dose escalation.  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