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   320516篇
  免费   8394篇
  国内免费   142篇
耳鼻咽喉   3418篇
儿科学   11565篇
妇产科学   6316篇
基础医学   38258篇
口腔科学   6322篇
临床医学   24692篇
内科学   57564篇
皮肤病学   4731篇
神经病学   31267篇
特种医学   14715篇
外科学   50886篇
综合类   3015篇
一般理论   50篇
预防医学   26078篇
眼科学   6006篇
药学   19383篇
  6篇
中国医学   840篇
肿瘤学   23940篇
  2023年   956篇
  2022年   647篇
  2021年   1513篇
  2020年   1385篇
  2019年   1710篇
  2018年   24709篇
  2017年   19697篇
  2016年   22597篇
  2015年   4037篇
  2014年   4305篇
  2013年   6851篇
  2012年   14551篇
  2011年   29092篇
  2010年   23269篇
  2009年   14607篇
  2008年   27594篇
  2007年   30167篇
  2006年   9342篇
  2005年   10763篇
  2004年   11472篇
  2003年   12364篇
  2002年   10407篇
  2001年   5662篇
  2000年   7211篇
  1999年   4034篇
  1998年   1809篇
  1997年   1547篇
  1996年   1139篇
  1995年   971篇
  1994年   965篇
  1993年   861篇
  1992年   924篇
  1991年   851篇
  1990年   863篇
  1989年   820篇
  1988年   698篇
  1987年   733篇
  1986年   657篇
  1985年   861篇
  1984年   795篇
  1983年   686篇
  1982年   729篇
  1981年   619篇
  1980年   614篇
  1979年   578篇
  1978年   506篇
  1977年   526篇
  1976年   459篇
  1975年   446篇
  1974年   442篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.

Objective

Low psoas muscle area is shown to be an indicator for worse postoperative outcome in patients undergoing vascular surgical. Additionally, it has been associated with longer durations of hospital stay in patients with cancer who undergo surgery and subsequently greater health care costs in Europe and the United States. We sought to evaluate this effect on hospital expenditure for patients undergoing vascular repair in a health care system with universal access.

Methods

Skeletal muscle mass was assessed on preoperative abdominal computed tomography scans of patients undergoing open aortic aneurysm repair in a retrospective fashion. The skeletal muscle index (SMI) was used to define low muscle mass. Health care costs were obtained for all patients and the relationship between a low SMI and higher costs was explored using linear regression and cross-sectional analysis.

Results

We included 156 patients (81.5% male) with a median age of 72 years undergoing elective surgery for infrarenal abdominal aortic aneurysm in this analysis. The median SMI for patients with low skeletal muscle mass was 53.21 cm2/kg and for patients without, 70.07 cm2/kg. Hospital duration of stay was 2 days longer in patients with low skeletal muscle mass as compared with patients with normal (14 days vs 11 days; P = .001), as was duration of intensive care stay (3 days vs 1 day; P = .01). The median overall hospital costs were €10,460 higher for patients with a low SMI as compared with patients with a normal physical constitution (€53,739 [interquartile range, €45,007-€62,471] vs €43,279 [interquartile range, €39,509-€47,049]; P = .001). After confounder adjustment, a low SMI was associated with a 14.68% cost increase in overall hospital costs, for a cost increase of €6521.

Conclusions

Low skeletal muscle mass is independently associated with higher hospital as well as intensive care costs in patients undergoing elective aortic aneurysm repair. Strategies to reduce this risk factor are warranted for these patients.  相似文献   
5.
6.

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   
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