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   103063篇
  免费   30471篇
  国内免费   1101篇
耳鼻咽喉   2449篇
儿科学   2672篇
妇产科学   2408篇
基础医学   3725篇
口腔科学   5195篇
临床医学   26431篇
内科学   25662篇
皮肤病学   3426篇
神经病学   13044篇
特种医学   4013篇
外科学   19129篇
综合类   143篇
现状与发展   40篇
一般理论   2篇
预防医学   13263篇
眼科学   2264篇
药学   1525篇
中国医学   30篇
肿瘤学   9214篇
  2024年   542篇
  2023年   5053篇
  2022年   1085篇
  2021年   2817篇
  2020年   5369篇
  2019年   2074篇
  2018年   6938篇
  2017年   7404篇
  2016年   8013篇
  2015年   8135篇
  2014年   10577篇
  2013年   12309篇
  2012年   4070篇
  2011年   3839篇
  2010年   7003篇
  2009年   9322篇
  2008年   3821篇
  2007年   2776篇
  2006年   3922篇
  2005年   2482篇
  2004年   1847篇
  2003年   1525篇
  2002年   1430篇
  2001年   1876篇
  2000年   1181篇
  1999年   1720篇
  1998年   2154篇
  1997年   1971篇
  1996年   2001篇
  1995年   1742篇
  1994年   1137篇
  1993年   956篇
  1992年   766篇
  1991年   649篇
  1990年   522篇
  1989年   535篇
  1988年   515篇
  1987年   375篇
  1986年   365篇
  1985年   307篇
  1984年   265篇
  1983年   321篇
  1982年   247篇
  1981年   215篇
  1980年   142篇
  1978年   142篇
  1977年   130篇
  1976年   94篇
  1975年   89篇
  1974年   99篇
排序方式: 共有10000条查询结果,搜索用时 375 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.
Intratumor heterogeneity is a main cause of the dismal prognosis of glioblastoma (GBM). Yet, there remains a lack of a uniform assessment of the degree of heterogeneity. With a multiscale approach, we addressed the hypothesis that intratumor heterogeneity exists on different levels comprising traditional regional analyses, but also innovative methods including computer-assisted analysis of tumor morphology combined with epigenomic data. With this aim, 157 biopsies of 37 patients with therapy-naive IDH-wildtype GBM were analyzed regarding the intratumor variance of protein expression of glial marker GFAP, microglia marker Iba1 and proliferation marker Mib1. Hematoxylin and eosin stained slides were evaluated for tumor vascularization. For the estimation of pixel intensity and nuclear profiling, automated analysis was used. Additionally, DNA methylation profiling was conducted separately for the single biopsies. Scoring systems were established to integrate several parameters into one score for the four examined modalities of heterogeneity (regional, cellular, pixel-level and epigenomic). As a result, we could show that heterogeneity was detected in all four modalities. Furthermore, for the regional, cellular and epigenomic level, we confirmed the results of earlier studies stating that a higher degree of heterogeneity is associated with poorer overall survival. To integrate all modalities into one score, we designed a predictor of longer survival, which showed a highly significant separation regarding the OS. In conclusion, multiscale intratumor heterogeneity exists in glioblastoma and its degree has an impact on overall survival. In future studies, the implementation of a broadly feasible heterogeneity index should be considered.  相似文献   
8.
9.
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