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   1781篇
  免费   68篇
  国内免费   4篇
耳鼻咽喉   12篇
儿科学   70篇
妇产科学   58篇
基础医学   187篇
口腔科学   45篇
临床医学   132篇
内科学   344篇
皮肤病学   36篇
神经病学   90篇
特种医学   133篇
外科学   205篇
综合类   60篇
预防医学   98篇
眼科学   81篇
药学   191篇
中国医学   8篇
肿瘤学   103篇
  2023年   12篇
  2022年   43篇
  2021年   61篇
  2020年   41篇
  2019年   49篇
  2018年   59篇
  2017年   28篇
  2016年   42篇
  2015年   46篇
  2014年   55篇
  2013年   74篇
  2012年   131篇
  2011年   130篇
  2010年   74篇
  2009年   67篇
  2008年   94篇
  2007年   79篇
  2006年   59篇
  2005年   60篇
  2004年   61篇
  2003年   54篇
  2002年   48篇
  2001年   58篇
  2000年   51篇
  1999年   45篇
  1998年   20篇
  1997年   12篇
  1996年   9篇
  1995年   7篇
  1994年   5篇
  1993年   9篇
  1992年   19篇
  1991年   25篇
  1990年   21篇
  1989年   17篇
  1988年   23篇
  1987年   17篇
  1986年   16篇
  1985年   16篇
  1984年   10篇
  1983年   10篇
  1982年   5篇
  1979年   15篇
  1977年   8篇
  1976年   8篇
  1975年   10篇
  1974年   7篇
  1972年   6篇
  1971年   6篇
  1968年   5篇
排序方式: 共有1853条查询结果,搜索用时 0 毫秒
1.

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   
2.
3.
4.
5.
Subjects from Muria gond tribal community (n = 258) as well as from Delhi (n = 100) were classified according to ABO blood groups, and were also assayed for malarial antibodies by ELISA technique. The distribution of ABO blood groups did not differ significantly in Muria gonds and Delhi subjects. Within Muria gonds the observed frequency of ABO blood groups did not differ significantly from the expected values. No significant difference was observed in the rate of seropositivity for malarial antibodies among subjects with different blood groups. Malarial parasitaemia, although observed more in individuals with blood group A, did not differ significantly as compared with other blood groups. We conclude that ABO blood groups do not show differential susceptibility to malaria.  相似文献   
6.
7.
8.
9.
Summary Liver specimens were collected at 114 (83 males and 31 females) autopsies on accident victims and on 4 stillborn infants in seven Canadian Cities. The age of the individuals ranged from newborn to 89 years with about 70% being 19–65 years. The level of lead in the samples was determined by atomic absorption spectroscopy using a carbon rod atomizer. The concentration of lead in liver was low (g/g: Mean, 0.37, Median 0.28) at birth and during infancy. In the stillborn infants it ranged from 0.30 to 0.77 (Mean 0.51). Male adults had an average level of 1.78 (Median 1.41) whereas in adult females the corresponding values were 0.65 and 0.57. The liver lead concentration peaked at about the end of the fourth decade in adult males. There was no indication of any regional differences.  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