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   2097013篇
  免费   156700篇
  国内免费   3962篇
耳鼻咽喉   27523篇
儿科学   70212篇
妇产科学   58795篇
基础医学   308453篇
口腔科学   59062篇
临床医学   195284篇
内科学   404814篇
皮肤病学   46180篇
神经病学   167833篇
特种医学   79192篇
外国民族医学   555篇
外科学   302970篇
综合类   46961篇
现状与发展   3篇
一般理论   939篇
预防医学   172376篇
眼科学   47710篇
药学   152901篇
  10篇
中国医学   3821篇
肿瘤学   112081篇
  2018年   22362篇
  2017年   17205篇
  2016年   19178篇
  2015年   21926篇
  2014年   30221篇
  2013年   46375篇
  2012年   62203篇
  2011年   66349篇
  2010年   38886篇
  2009年   37095篇
  2008年   62215篇
  2007年   66456篇
  2006年   66391篇
  2005年   64459篇
  2004年   62313篇
  2003年   59820篇
  2002年   57925篇
  2001年   92767篇
  2000年   94892篇
  1999年   80095篇
  1998年   22933篇
  1997年   20757篇
  1996年   21045篇
  1995年   20094篇
  1994年   18682篇
  1993年   17512篇
  1992年   64155篇
  1991年   62944篇
  1990年   61620篇
  1989年   59538篇
  1988年   54638篇
  1987年   54311篇
  1986年   51393篇
  1985年   49022篇
  1984年   37244篇
  1983年   32066篇
  1982年   19213篇
  1981年   17381篇
  1979年   34944篇
  1978年   25591篇
  1977年   21467篇
  1976年   20164篇
  1975年   21435篇
  1974年   26078篇
  1973年   25382篇
  1972年   23863篇
  1971年   22221篇
  1970年   20826篇
  1969年   19571篇
  1968年   18173篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
1.
2.
3.
4.
5.
6.
7.
8.

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   
9.
Abstract

The study examines Parental Feeding Practices (PFP) in relation to adherence to the Mediterranean Diet (MD) and children’s weight status. It’s a cross-sectional study of 402 parents (68.4% mothers), with children aged 2–12 years. Parents completed the Comprehensive Parental Feeding Questionnaire and the Mediterranean Diet Quality Index for children and adolescents (KIDMED), evaluating children’s adherence to the MD. Logistic regression showed that in children aged 2–<6 years, “emotion regulation/food as reward” and “pressure” decrease MD adherence (OR?=?0.186, p?<?0.0001 and OR?=?0.496, p?=?0.004), and “monitoring” decrease excess body weight (OR?=?0.284, p?=?0.009). In older children (6–12 years), “healthy eating guidance” and “monitoring” increase MD adherence (OR?=?3.262, p?=?0.001 and OR?=?3.147, p?<?0.0001), “child control” decreases MD adherence (OR?=?0.587, p?=?0.049), “pressure” decrease excess body weight (OR?=?0.495, p?<?0.0001) and “restriction” increase excess body weight (OR?=?1.784, p?=?0.015). “Healthy eating guidance” and “monitoring” seem to be the best PFP employed, in terms of children’s MD adherence and weight status.  相似文献   
10.

Background

The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.

Methods

A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.

Results

Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.

Conclusions

In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler.  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