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   185875篇
  免费   67403篇
  国内免费   1526篇
耳鼻咽喉   3801篇
儿科学   6678篇
妇产科学   3196篇
基础医学   21184篇
口腔科学   9909篇
临床医学   36726篇
内科学   49858篇
皮肤病学   10864篇
神经病学   24531篇
特种医学   6677篇
外科学   33186篇
综合类   621篇
现状与发展   40篇
一般理论   36篇
预防医学   17054篇
眼科学   3950篇
药学   8836篇
中国医学   1282篇
肿瘤学   16375篇
  2024年   544篇
  2023年   5147篇
  2022年   1470篇
  2021年   4772篇
  2020年   10615篇
  2019年   13168篇
  2018年   15650篇
  2017年   17138篇
  2016年   18317篇
  2015年   18637篇
  2014年   21206篇
  2013年   23675篇
  2012年   9093篇
  2011年   8995篇
  2010年   15566篇
  2009年   14395篇
  2008年   6552篇
  2007年   4474篇
  2006年   5581篇
  2005年   3863篇
  2004年   3052篇
  2003年   2745篇
  2002年   2648篇
  2001年   3255篇
  2000年   2442篇
  1999年   2516篇
  1998年   2292篇
  1997年   2103篇
  1996年   2135篇
  1995年   1839篇
  1994年   1222篇
  1993年   995篇
  1992年   1042篇
  1991年   852篇
  1990年   760篇
  1989年   764篇
  1988年   730篇
  1987年   564篇
  1986年   519篇
  1985年   444篇
  1984年   383篇
  1983年   403篇
  1982年   299篇
  1981年   263篇
  1980年   185篇
  1979年   184篇
  1978年   201篇
  1977年   180篇
  1976年   128篇
  1974年   123篇
排序方式: 共有10000条查询结果,搜索用时 15 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.
9.
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   
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