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   12914篇
  免费   1088篇
  国内免费   50篇
耳鼻咽喉   86篇
儿科学   470篇
妇产科学   358篇
基础医学   1744篇
口腔科学   309篇
临床医学   1592篇
内科学   2468篇
皮肤病学   136篇
神经病学   1392篇
特种医学   329篇
外国民族医学   1篇
外科学   1196篇
综合类   107篇
一般理论   39篇
预防医学   2020篇
眼科学   139篇
药学   844篇
中国医学   5篇
肿瘤学   817篇
  2024年   19篇
  2023年   151篇
  2022年   174篇
  2021年   387篇
  2020年   298篇
  2019年   468篇
  2018年   480篇
  2017年   397篇
  2016年   440篇
  2015年   392篇
  2014年   525篇
  2013年   709篇
  2012年   939篇
  2011年   968篇
  2010年   529篇
  2009年   431篇
  2008年   761篇
  2007年   753篇
  2006年   673篇
  2005年   598篇
  2004年   578篇
  2003年   518篇
  2002年   506篇
  2001年   190篇
  2000年   176篇
  1999年   179篇
  1998年   133篇
  1997年   118篇
  1996年   113篇
  1995年   87篇
  1994年   81篇
  1993年   62篇
  1992年   136篇
  1991年   116篇
  1990年   111篇
  1989年   110篇
  1988年   94篇
  1987年   66篇
  1986年   69篇
  1985年   66篇
  1984年   64篇
  1983年   32篇
  1982年   35篇
  1980年   27篇
  1979年   27篇
  1978年   20篇
  1977年   26篇
  1975年   20篇
  1972年   17篇
  1968年   16篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
Sustainability     
Medicine, Health Care and Philosophy -  相似文献   
3.
4.

Objectives

Short successive periods of skeletal muscle disuse have been suggested to substantially contribute to the observed loss of skeletal muscle mass over the life span. Hospitalization of older individuals due to acute illness, injury, or major surgery generally results in a mean hospital stay of 5 to 7 days, during which the level of physical activity is strongly reduced. We hypothesized that hospitalization following elective total hip arthroplasty is accompanied by substantial leg muscle atrophy in older men and women.

Design and participants

Twenty-six older patients (75 ± 1 years) undergoing elective total hip arthroplasty participated in this observational study.

Measurements

On hospital admission and on the day of discharge, computed tomographic (CT) scans were performed to assess muscle cross-sectional area (CSA) of both legs. During surgery and on the day of hospital discharge, a skeletal muscle biopsy was taken from the m. vastus lateralis of the operated leg to assess muscle fiber type–specific CSA.

Results

An average of 5.6 ± 0.3 days of hospitalization resulted in a significant decline in quadriceps (?3.4% ± 1.0%) and thigh muscle CSA (?4.2% ± 1.1%) in the nonoperated leg (P < .05). Edema resulted in a 10.3% ± 1.7% increase in leg CSA in the operated leg (P < .05). At hospital admission, muscle fiber CSA was smaller in the type II vs type I fibers (3326 ± 253 μm2 vs 4075 ± 279 μm2, respectively; P < .05). During hospitalization, type I and II muscle fiber CSA tended to increase, likely due to edema in the operated leg (P = .10).

Conclusions

Six days of hospitalization following elective total hip arthroplasty leads to substantial leg muscle atrophy in older patients. Effective intervention strategies are warranted to prevent the loss of muscle mass induced by short periods of muscle disuse during hospitalization.  相似文献   
5.

Objectives

The current study investigated the effects of two exercise interventions on cognitive function amongst breast cancer survivors.

Design

Pilot randomised-controlled trial.

Methods

Seventeen female cancer survivors (mean: 62.9 ± 7.8 years) were randomised into three groups: high-intensity interval training (HIIT, n = 6); moderate-intensity continuous training (MOD, n = 5); or wait-list control (CON, n = 6). The HIIT and MOD groups exercised on a cycle ergometer 3 days/week for 12-weeks. Primary outcomes were cognitive function assessments utilising CogState. Secondary outcomes were resting middle cerebral artery blood flow velocity, cerebrovascular reactivity and aerobic fitness (VO2peak). Data were analysed with General Linear Mixed Models and Cohen’s d effect sizes were calculated.

Results

All 17 participants who were randomised were available for follow-up analysis and adherence was similar for HIIT and MOD (78.7 ± 13.2% vs 79.4 ± 12.0%; p = 0.93). Although there were no significant differences in the cognitive and cerebrovascular outcomes, HIIT produced moderate to large positive effects in comparison to MOD and CON for outcomes including episodic memory, working memory, executive function, cerebral blood flow and cerebrovascular reactivity. HIIT significantly increased VO2peak by 19.3% (d = 1.28) and MOD had a non-significant 5.6% (d = 0.72) increase, compared to CON which had a 2.6% decrease.

Conclusions

This study provides preliminary evidence that HIIT may be an effective exercise intervention to improve cognitive performance, cerebrovascular function and aerobic fitness in breast cancer survivors. Considering the sample size is small, these results should be confirmed through larger clinical trials.  相似文献   
6.
7.
8.
9.

Background  

Self-report recall questionnaires are commonly used to measure physical activity, energy expenditure and time use in children and adolescents. However, self-report questionnaires show low to moderate validity, mainly due to inaccuracies in recalling activity in terms of duration and intensity. Aside from recall errors, inaccuracies in estimating energy expenditure from self-report questionnaires are compounded by a lack of data on the energy cost of everyday activities in children and adolescents. This article describes the development of the Multimedia Activity Recall for Children and Adolescents (MARCA), a computer-delivered use-of-time instrument designed to address both the limitations of self-report recall questionnaires in children, and the lack of energy cost data in children.  相似文献   
10.
INTRODUCTION: There are no measures of health-related absenteeism and presenteeism validated for use in the large and increasing US Spanish-speaking population. Before using a Spanish translation of an available English-language questionnaire, the linguistic validity of the Spanish version must be established to ensure its conceptual equivalence to the original and its cultural appropriateness. OBJECTIVE: The objective of this study was to evaluate the linguistic validity of the US Spanish version of the Work Productivity and Activity Impairment questionnaire, General Health Version (WPAI:GH). METHODS: A US Spanish translation of the US English WPAI:GH was created through a reiterative process of creating harmonized forward and back translations by independent translators. Spanish-speaking and English-speaking subjects residing in the US self-administered the WPAI:GH in their primary language and were subsequently debriefed by a bilingual (Spanish-English) interviewer. RESULTS: US Spanish subjects (N = 31) and English subjects (N = 35), stratified equally by educational level, with and without a high school degree participated in the study. The WPAI-GH item comprehension rate was 98.6% for Spanish and 99.6% for English. Response revision rates during debriefing were 1.6% for Spanish and 0.5% for English. Responses to hypothetical scenarios indicated that both language versions adequately differentiate sick time taken for health and non-health reasons and between absenteeism and presenteeism. CONCLUSION: Linguistic validity of the US Spanish translation of the WPAI:GH was established among a diverse US Spanish-speaking population, including those with minimal education.  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