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   135981篇
  免费   33031篇
  国内免费   1104篇
耳鼻咽喉   2859篇
儿科学   4083篇
妇产科学   3443篇
基础医学   7330篇
口腔科学   5743篇
临床医学   31574篇
内科学   31281篇
皮肤病学   3958篇
神经病学   15826篇
特种医学   4706篇
外科学   22198篇
综合类   1046篇
现状与发展   40篇
一般理论   63篇
预防医学   18040篇
眼科学   2908篇
药学   3902篇
  2篇
中国医学   58篇
肿瘤学   11056篇
  2024年   756篇
  2023年   5162篇
  2022年   1390篇
  2021年   3360篇
  2020年   5706篇
  2019年   2595篇
  2018年   7513篇
  2017年   7755篇
  2016年   8387篇
  2015年   8582篇
  2014年   11281篇
  2013年   13469篇
  2012年   5770篇
  2011年   5776篇
  2010年   7982篇
  2009年   9948篇
  2008年   5440篇
  2007年   4526篇
  2006年   5622篇
  2005年   4119篇
  2004年   3484篇
  2003年   2988篇
  2002年   2657篇
  2001年   2824篇
  2000年   2156篇
  1999年   2498篇
  1998年   2448篇
  1997年   2271篇
  1996年   2248篇
  1995年   1972篇
  1994年   1358篇
  1993年   1159篇
  1992年   1473篇
  1991年   1374篇
  1990年   1204篇
  1989年   1156篇
  1988年   1124篇
  1987年   946篇
  1986年   948篇
  1985年   861篇
  1984年   727篇
  1983年   761篇
  1982年   538篇
  1981年   485篇
  1980年   390篇
  1979年   516篇
  1978年   456篇
  1977年   399篇
  1976年   337篇
  1974年   383篇
排序方式: 共有10000条查询结果,搜索用时 859 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.
Kinase alterations are increasingly recognised as oncogenic drivers in mesenchymal tumours. Infantile fibrosarcoma and the related renal tumour, congenital mesoblastic nephroma, were among the first solid tumours shown to harbour recurrent tyrosine kinase fusions, with the canonical ETV6::NTRK3 fusion identified more than 20 years ago. Although targeted testing has long been used in diagnosis, the advent of more robust sequencing techniques has driven the discovery of kinase alterations in an array of mesenchymal tumours. As our ability to identify these genetic alterations has improved, as has our recognition and understanding of the tumours that harbour these alterations. Specifically, this study will focus upon mesenchymal tumours harbouring NTRK or other kinase alterations, including tumours with an infantile fibrosarcoma-like appearance, spindle cell tumours resembling lipofibromatosis or peripheral nerve sheath tumours and those occurring in adults with a fibrosarcoma-like appearance. As publications describing the histology of these tumours increase so, too, do the variety kinase alterations reported, now including NTRK1/2/3, RET, MET, RAF1, BRAF, ALK, EGFR and ABL1 fusions or alterations. To date, these tumours appear locally aggressive and rarely metastatic, without a clear link between traditional features used in histological grading (e.g. mitotic activity, necrosis) and outcome. However, most of these tumours are amenable to new targeted therapies, making their recognition of both diagnostic and therapeutic import. The goal of this study is to review the clinicopathological features of tumours with NTRK and other tyrosine kinase alterations, discuss the most common differential diagnoses and provide recommendations for molecular confirmation with associated treatment implications.  相似文献   
4.
5.
6.
7.
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