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   3777499篇
  免费   318191篇
  国内免费   27061篇
耳鼻咽喉   53027篇
儿科学   112358篇
妇产科学   98874篇
基础医学   581951篇
口腔科学   105684篇
临床医学   341083篇
内科学   664445篇
皮肤病学   98053篇
神经病学   314089篇
特种医学   150211篇
外国民族医学   622篇
外科学   584034篇
综合类   140255篇
现状与发展   63篇
一般理论   2322篇
预防医学   296812篇
眼科学   89514篇
药学   275570篇
  204篇
中国医学   21825篇
肿瘤学   191755篇
  2021年   60410篇
  2020年   41985篇
  2019年   63745篇
  2018年   77161篇
  2017年   59644篇
  2016年   65048篇
  2015年   81802篇
  2014年   117741篇
  2013年   182052篇
  2012年   108425篇
  2011年   109187篇
  2010年   125735篇
  2009年   128292篇
  2008年   91682篇
  2007年   95448篇
  2006年   105273篇
  2005年   100129篇
  2004年   98831篇
  2003年   89549篇
  2002年   79100篇
  2001年   126827篇
  2000年   120703篇
  1999年   116752篇
  1998年   62998篇
  1997年   60208篇
  1996年   56974篇
  1995年   57705篇
  1994年   51905篇
  1993年   48051篇
  1992年   81449篇
  1991年   77134篇
  1990年   73625篇
  1989年   72760篇
  1988年   67720篇
  1987年   66103篇
  1986年   62876篇
  1985年   62223篇
  1984年   54315篇
  1983年   48761篇
  1982年   43211篇
  1981年   40428篇
  1980年   38149篇
  1979年   46181篇
  1978年   39126篇
  1977年   35731篇
  1976年   32141篇
  1975年   32195篇
  1974年   34289篇
  1973年   32936篇
  1972年   31389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.
目的 了解我国老年人中医证候分布特征,为中医药辨治老年人提供参考依据。方法 系统检索中国知识基础设施(CNKI)、中文科技期刊数据库(CCD)、万方数据资源系统数据库(CSPD),纳入研究对象为老年人的临床流行病学调查研究文献,对其调查目的、调查疾病及调查结果等进行描述统计。结果 ①最终纳入168篇文献,其中2010至2020年之间发表138篇(82.14%);调查地区涵盖全国28个省市自治区,共纳入43948例老年人,累计覆盖340个研究中心;②主要研究结果显示,老年人中医证候阴虚阳亢证(10.05%)>血瘀证(9.5%)>痰浊(湿)证(8.91%)>阴阳两虚证(4.98%)>痰瘀互结证(4.96%);单元证分布阴虚证(14.70%)>痰证(11.22%)>气虚证(7.15%)>肾虚证(4.72%)>血瘀证(4.18%);涉及病变脏腑肾>肝>脾>肺>心。结论 根据统计结果,可以看出老年人证候分布虚证多于实证,虚证中又以阴虚证、气虚证最为多见,实证常见血瘀证、痰浊(湿)证等,且多见痰瘀互结证;老年人五脏皆损,其中又以肾、肝、脾功能失调最为突出。  相似文献   
7.
中医学古籍中罕有关于“胰腺”的明确记载,缺乏直观、系统的理论论述。本文试图通过对各个时期具有代表性的医学典籍所记载内容的分析,结合现代解剖学相关理论,梳理中医学对胰腺实体解剖的认识过程。通过分析,笔者认为中医学对胰腺实体解剖的认识具有阶段性:①先秦两汉时期,存在胰腺实体解剖,但并非认为胰腺是脏器;②唐宋时期,胰腺实体解剖更加清晰,在医学上胰腺附属于脾,并非为独立的脏器;③明清时期,胰腺实体解剖明确,部分医家以独立脏器论之,出现“脾”、“胰”之争。中医学理论缺少对胰腺的单独论述,目前学界的主流观点多为“胰属脾”,线性归属以脾笼统代之略显单薄,不利于理论的丰富与发展。笔者认为胰腺藏象应独立于脾单独讨论,现代解剖学对胰腺命名同一,形态结构清楚,位置描述明确,可直接补充进中医学胰腺藏象(藏)理论中,为完善胰腺藏象理论搭建解剖学基础。  相似文献   
8.
9.

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   
10.
【摘要】 目的 探讨经动脉栓塞术(transarterial embolization,TAE)治疗食管癌出血的有效性及安全性。方法 收集2018年1月至2020年12月行TAE治疗的14例食管癌出血患者的临床资料、技术成功率、临床成功率,严重并发症情况。评估TAE治疗的有效性及安全性。结果 14例患者中导管成功选择性插入靶动脉并行栓塞患者11例。9例患者接受治疗后未再出现出血征象。出血的主要责任血管为胃左动脉7例,支气管动脉6例和食管固有动脉6例。栓塞材料为微弹簧圈、明胶海绵颗粒及聚乙烯醇颗粒。常见不良反应有疼痛、发热,其中1例患者发生食管瘘。结论 对于内科治疗无效的食管癌出血,TAE可以起到良好的疗效。食管瘘作为术后的严重并发症,需特别注意预防。对于胸段食管癌及食管胃交界处癌,最常见的责任血管为胃左动脉、支气管动脉及食管固有动脉。  相似文献   
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