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   2419459篇
  免费   198464篇
  国内免费   7022篇
耳鼻咽喉   34773篇
儿科学   73379篇
妇产科学   63376篇
基础医学   338850篇
口腔科学   68095篇
临床医学   221346篇
内科学   473706篇
皮肤病学   48436篇
神经病学   202610篇
特种医学   97558篇
外国民族医学   902篇
外科学   364113篇
综合类   66423篇
现状与发展   9篇
一般理论   978篇
预防医学   194662篇
眼科学   56684篇
药学   182867篇
  59篇
中国医学   6969篇
肿瘤学   129150篇
  2018年   25252篇
  2017年   20060篇
  2016年   21634篇
  2015年   25123篇
  2014年   36019篇
  2013年   53467篇
  2012年   72566篇
  2011年   76557篇
  2010年   45812篇
  2009年   43688篇
  2008年   72064篇
  2007年   76089篇
  2006年   76930篇
  2005年   74415篇
  2004年   71187篇
  2003年   68704篇
  2002年   67677篇
  2001年   113512篇
  2000年   117342篇
  1999年   98931篇
  1998年   28247篇
  1997年   25897篇
  1996年   25738篇
  1995年   24846篇
  1994年   23398篇
  1993年   21668篇
  1992年   79495篇
  1991年   76489篇
  1990年   73625篇
  1989年   70888篇
  1988年   65899篇
  1987年   64832篇
  1986年   61350篇
  1985年   58418篇
  1984年   44234篇
  1983年   37660篇
  1982年   22888篇
  1981年   20334篇
  1979年   41300篇
  1978年   28987篇
  1977年   24346篇
  1976年   22832篇
  1975年   23965篇
  1974年   29643篇
  1973年   28043篇
  1972年   26228篇
  1971年   24152篇
  1970年   22752篇
  1969年   21087篇
  1968年   19136篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.

Background and aims

Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.

Methods and results

In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.

Conclusion

SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE.  相似文献   
25.

Background

Lung ultrasound can accelerate the diagnosis of life-threatening diseases in adults with respiratory symptoms.

Objective

Systematically review the accuracy of lung ultrasonography (LUS) for emergency diagnosis of pneumonia, acute heart failure, and exacerbation of chronic obstructive pulmonary disease (COPD)/asthma in adults.

Methods

PubMed, Embase, Scopus, Web of Science, and LILACS (Literatura Latino Americana e do Caribe em Ciências da Saúde; until 2016) were searched for prospective diagnostic accuracy studies. Rutter-Gatsonis hierarchical summary receiver operating characteristic method was used to measure the overall accuracy of LUS and Reitsma bivariate model to measure the accuracy of the different sonographic signs. This review was previously registered in PROSPERO (Centre for Reviews and Dissemination, University of York, York, UK; CRD42016048085).

Results

Twenty-five studies were included: 14 assessing pneumonia, 14 assessing acute heart failure, and four assessing exacerbations of COPD/asthma. The area under the summary receiver operating characteristic curve of LUS was 0.948 for pneumonia, 0.914 for acute heart failure, and 0.906 for exacerbations of COPD/asthma. In patients suspected to have pneumonia, consolidation had sensitivity of 0.82 (95% confidence interval [CI] 0.74–0.88) and specificity of 0.94 (95% CI 0.85–0.98) for this disease. In acutely dyspneic patients, modified diffuse interstitial syndrome had sensitivity of 0.90 (95% CI 0.87–0.93) and specificity of 0.93 (95% CI 0.91–0.95) for acute heart failure, whereas B-profile had sensitivity of 0.93 (95% CI 0.72–0.98) and specificity of 0.92 (95% CI 0.79–0.97) for this disease in patients with respiratory failure. In patients with acute dyspnea or respiratory failure, the A-profile without PLAPS (posterior-lateral alveolar pleural syndrome) had sensitivity of 0.78 (95% CI 0.67–0.86) and specificity of 0.94 (95% CI 0.89–0.97) for exacerbations of COPD/asthma.

Conclusion

Lung ultrasound is an accurate tool for the emergency diagnosis of pneumonia, acute heart failure, and exacerbations of COPD/asthma.  相似文献   
26.

Introduction

In the United States there has been a large increase in participation in lacrosse for both males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.

Methods

We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.

Results

A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R2?=?0.823; p?=?0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R2?=?0.800; p?=?0.007), but again, there was no significance for female injury count (R2?=?0.417; p?=?0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the type of injury recorded.

Conclusion

The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency department.  相似文献   
27.
通过文献研究、问卷调查、专家访谈、现地调研等方法,分析医院离退休干部参与社会治理的现状及影响因素,探讨社区对离退休干部参与社会治理的需求,提出通过党建引领医院离退休干部参与社会治理的“1235”模式,并给出具体的操作路径,以期为推动医院离退休干部积极参与社会治理提供参考。  相似文献   
28.
29.
30.
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