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   4368844篇
  免费   367360篇
  国内免费   19806篇
耳鼻咽喉   62231篇
儿科学   135068篇
妇产科学   114880篇
基础医学   668072篇
口腔科学   121418篇
临床医学   398247篇
内科学   790134篇
皮肤病学   104828篇
神经病学   372229篇
特种医学   174245篇
外国民族医学   967篇
外科学   664133篇
综合类   136720篇
现状与发展   41篇
一般理论   2596篇
预防医学   367886篇
眼科学   103493篇
药学   312119篇
  83篇
中国医学   14708篇
肿瘤学   211912篇
  2021年   58443篇
  2020年   37520篇
  2019年   60390篇
  2018年   75137篇
  2017年   57242篇
  2016年   63512篇
  2015年   77524篇
  2014年   112874篇
  2013年   177535篇
  2012年   122740篇
  2011年   126580篇
  2010年   125846篇
  2009年   128071篇
  2008年   111993篇
  2007年   118786篇
  2006年   128082篇
  2005年   123096篇
  2004年   123005篇
  2003年   113540篇
  2002年   103940篇
  2001年   158572篇
  2000年   154905篇
  1999年   143538篇
  1998年   72733篇
  1997年   68902篇
  1996年   66312篇
  1995年   62143篇
  1994年   56144篇
  1993年   52032篇
  1992年   106042篇
  1991年   101401篇
  1990年   96463篇
  1989年   94085篇
  1988年   87599篇
  1987年   85890篇
  1986年   81560篇
  1985年   79899篇
  1984年   67255篇
  1983年   59939篇
  1982年   48578篇
  1981年   45224篇
  1980年   42496篇
  1979年   59110篇
  1978年   47715篇
  1977年   42187篇
  1976年   39202篇
  1975年   38663篇
  1974年   43373篇
  1973年   41513篇
  1972年   38939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.
Quality of Life Research - The COVID-19 pandemic might add to the stressors experienced by people living with rheumatic diseases. This study aimed to examine rheumatic patients’ functional...  相似文献   
4.
Molnár  B.  Aroca  S.  Dobos  A.  Orbán  K.  Szabó  J.  Windisch  P.  Stähli  A.  Sculean  A. 《Clinical oral investigations》2022,26(12):7135-7142
Clinical Oral Investigations - To evaluate t he long-term outcomes following treatment of RT 1 multiple adjacent gingival recessions (MAGR) using the modified coronally advanced tunnel (MCAT) with...  相似文献   
5.

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   
6.
综述了脑血管介入术穿刺点压迫方法(包括人工压迫、弹力带加压、压迫器加压、血管闭合装置压迫、止血敷料压迫、气囊加压6种)、止血压力以及压迫时间,提出由于穿刺点和压迫方法的不同,其压迫时间、减压时间和压力大小等需要进一步探讨,为脑血管介入术后患者穿刺点的临床护理提供参考。  相似文献   
7.
8.

Interstitial lung disease (ILD) represents a significant cause of morbidity and mortality in systemic sclerosis (SSc). The purpose of this study was to examine recirculating lymphocytes from SSc patients for potential biomarkers of interstitial lung disease (ILD). Peripheral blood mononuclear cells (PBMCs) were isolated from patients with SSc and healthy controls enrolled in the Vanderbilt University Myositis and Scleroderma Treatment Initiative Center cohort between 9/2017–6/2019. Clinical phenotyping was performed by chart abstraction. Immunophenotyping was performed using both mass cytometry and fluorescence cytometry combined with t-distributed stochastic neighbor embedding analysis and traditional biaxial gating. This study included 34 patients with SSc-ILD, 14 patients without SSc-ILD, and 25 healthy controls. CD21lo/neg cells are significantly increased in SSc-ILD but not in SSc without ILD (15.4 ± 13.3% vs. 5.8 ± 0.9%, p = 0.002) or healthy controls (5.0 ± 0.5%, p < 0.0001). While CD21lo/neg B cells can be identified from a single biaxial gate, tSNE analysis reveals that the biaxial gate is comprised of multiple distinct subsets, all of which are increased in SSc-ILD. CD21lo/neg cells in both healthy controls and SSc-ILD are predominantly tBET positive and do not have intracellular CD21. Immunohistochemistry staining demonstrated that CD21lo/neg B cells diffusely infiltrate the lung parenchyma of an SSc-ILD patient. Additional work is needed to validate this biomarker in larger cohorts and longitudinal studies and to understand the role of these cells in SSc-ILD.

  相似文献   
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