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   3483356篇
  免费   298776篇
  国内免费   17738篇
耳鼻咽喉   47375篇
儿科学   110010篇
妇产科学   89630篇
基础医学   552627篇
口腔科学   93739篇
临床医学   320934篇
内科学   611627篇
皮肤病学   91813篇
神经病学   295549篇
特种医学   136123篇
外国民族医学   317篇
外科学   529363篇
综合类   117713篇
现状与发展   42篇
一般理论   2367篇
预防医学   297855篇
眼科学   79488篇
药学   242379篇
  135篇
中国医学   15049篇
肿瘤学   165735篇
  2021年   58111篇
  2020年   37659篇
  2019年   59852篇
  2018年   73044篇
  2017年   56231篇
  2016年   61324篇
  2015年   76539篇
  2014年   111602篇
  2013年   177025篇
  2012年   99828篇
  2011年   100567篇
  2010年   121858篇
  2009年   125351篇
  2008年   85857篇
  2007年   88936篇
  2006年   98492篇
  2005年   93588篇
  2004年   94109篇
  2003年   84725篇
  2002年   74243篇
  2001年   103727篇
  2000年   96022篇
  1999年   95739篇
  1998年   64752篇
  1997年   62825篇
  1996年   60930篇
  1995年   56309篇
  1994年   50550篇
  1993年   47194篇
  1992年   67592篇
  1991年   64848篇
  1990年   61482篇
  1989年   60652篇
  1988年   56460篇
  1987年   55212篇
  1986年   52645篇
  1985年   52237篇
  1984年   48147篇
  1983年   44322篇
  1982年   41700篇
  1981年   39426篇
  1980年   37153篇
  1979年   40659篇
  1978年   36258篇
  1977年   32835篇
  1976年   30118篇
  1975年   29003篇
  1974年   30484篇
  1973年   29598篇
  1972年   27852篇
排序方式: 共有10000条查询结果,搜索用时 179 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.
7.

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   
8.
9.
肠易激综合征是临床常见的功能性胃肠病之一。由于多数患者的症状经过一线药物治疗后仍不能得到较好改善,许多患者为获得更好的治疗效果,转向选择补充与替代疗法进行治疗。然而,由于研究质量和数量的限制,大部分治疗肠易激综合征的补充与替代疗法并未被相关共识和指南所推荐。本文从补充与替代疗法的分类入手,从天然产品、身心治疗、传统医药3个方面就目前国内外常用的补充与替代疗法治疗肠易激综合征的研究进行概述,以期为临床工作者和患者更好地了解和应用提供帮助。  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