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   9260篇
  免费   661篇
  国内免费   30篇
耳鼻咽喉   61篇
儿科学   307篇
妇产科学   256篇
基础医学   1354篇
口腔科学   158篇
临床医学   1074篇
内科学   1905篇
皮肤病学   272篇
神经病学   1058篇
特种医学   178篇
外科学   895篇
综合类   36篇
一般理论   10篇
预防医学   951篇
眼科学   150篇
药学   523篇
中国医学   18篇
肿瘤学   745篇
  2024年   10篇
  2023年   90篇
  2022年   165篇
  2021年   378篇
  2020年   235篇
  2019年   324篇
  2018年   387篇
  2017年   268篇
  2016年   283篇
  2015年   286篇
  2014年   444篇
  2013年   554篇
  2012年   830篇
  2011年   769篇
  2010年   406篇
  2009年   362篇
  2008年   525篇
  2007年   628篇
  2006年   574篇
  2005年   545篇
  2004年   464篇
  2003年   371篇
  2002年   362篇
  2001年   45篇
  2000年   44篇
  1999年   56篇
  1998年   67篇
  1997年   50篇
  1996年   41篇
  1995年   33篇
  1994年   36篇
  1993年   25篇
  1992年   26篇
  1991年   10篇
  1990年   14篇
  1989年   14篇
  1988年   10篇
  1987年   6篇
  1986年   18篇
  1985年   12篇
  1984年   11篇
  1983年   18篇
  1982年   13篇
  1981年   8篇
  1980年   15篇
  1978年   6篇
  1977年   8篇
  1975年   6篇
  1970年   7篇
  1933年   7篇
排序方式: 共有9951条查询结果,搜索用时 15 毫秒
161.
162.
163.

Purpose

To describe total fluid intake (TFI) according to socio-demographic characteristics in children and adolescents worldwide.

Methods

Data of 3611 children (4–9 years) and 8109 adolescents (10–18 years) were retrieved from 13 cross-sectional surveys (47 % males). In three countries, school classes were randomly recruited with stratified cluster sampling design. In the other countries, participants were randomly recruited based on a quota method. TFI (drinking water and beverages of all kinds) was obtained with a fluid-specific record over 7 consecutive days. Adequacy was assessed by comparing TFI to 80 % of adequate intake (AI) for total water intake set by European Food Safety Authority. Data on height, weight and socio-economic level were collected in most countries.

Results

The mean (SD) TFI ranged from [1.32 (0.68)] to [1.35 (0.71)] L/day. Non-adherence to AIs for fluids ranged from 10 % (Uruguay) to >90 % (Belgium). Females were more likely to meet the AIs for fluids than males (4–9 years: 28 %, OR 0.72, p = 0.002; 10–18 years: 20 %, OR 0.80, p = 0.001), while adolescents were less likely to meet the AI than children (OR 1.645, p < 0.001 in males and OR 1.625, p < 0.001 in females).

Conclusions

A high proportion of children and adolescents are at risk of an inadequate fluid intake. This risk is especially high in males and adolescents when compared with females or children categories. This highlights water intake among young populations as an issue of global concern.
  相似文献   
164.
165.
Hou  Wenjing  Zhao  Jun  He  Rui  Li  Jing  Ou  Yuan  Du  Mingshan  Xiong  Xuanqi  Xie  Bing  Li  Lian  Zhou  Xiaoyue  Zuo  Panli  Raithel  Esther  Zhang  Zhuoli  Chen  Wei 《Clinical rheumatology》2021,40(5):1997-2006
Clinical Rheumatology - To determine the reproducibility of the automatic cartilage segmentation method using a prototype KneeCaP software (version 1.3; Siemens Healthcare, Erlangen, Germany) and...  相似文献   
166.
Metabolic Brain Disease - Schizophrenia is a debilitating mental illness. Levels of oxytocin have been proposed as a biomarker of schizophrenia; however, the observed levels of oxytocin in...  相似文献   
167.
Journal of Gastroenterology - Functional dyspepsia (FD) is differentiated into two subgroups: the postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS). Acute gastroenteritis and...  相似文献   
168.
AIDS and Behavior - Many men with HIV (MWH) in Uganda desire children, yet seldom receive reproductive counseling related to HIV care. Because men are under engaged in safer conception programming,...  相似文献   
169.
A previous investigation reported that cross-sectional age differences in Digit Symbol Substitution (DSS) test performance reflect declines in perceptual processing speed. Support for the tenability of the processing speed hypothesis requires examining whether longitudinal age-related change in DSS performance is largely mediated by changes in speed. The present study used data from the Victoria Longitudinal Study to examine patterns and predictors of longitudinal change in DSS for 512 older adults (M(age) = 68.37 years, SD = 7.43). On the basis of multilevel modeling, baseline DSS performance was poorer for older participants and men, with longitudinal declines more pronounced with increasing age and decreasing speed. In contrast to the present cross-sectional findings, statistical control of change trajectories in perceptual speed using the same data did not substantially attenuate age changes. These discrepancies suggest different sources of variance may underlie cross-sectional age differences and longitudinal age changes for DSS.  相似文献   
170.
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