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   228242篇
  免费   37627篇
  国内免费   2621篇
耳鼻咽喉   6237篇
儿科学   7582篇
妇产科学   3972篇
基础医学   12931篇
口腔科学   3121篇
临床医学   34415篇
内科学   63060篇
皮肤病学   8582篇
神经病学   22093篇
特种医学   9313篇
外国民族医学   5篇
外科学   53843篇
综合类   1379篇
现状与发展   72篇
一般理论   101篇
预防医学   13994篇
眼科学   4855篇
药学   6324篇
中国医学   128篇
肿瘤学   16483篇
  2024年   532篇
  2023年   5088篇
  2022年   1559篇
  2021年   4923篇
  2020年   6909篇
  2019年   3807篇
  2018年   9214篇
  2017年   8629篇
  2016年   9673篇
  2015年   9875篇
  2014年   17671篇
  2013年   18820篇
  2012年   10663篇
  2011年   10898篇
  2010年   13198篇
  2009年   16633篇
  2008年   10525篇
  2007年   9104篇
  2006年   11380篇
  2005年   8652篇
  2004年   7646篇
  2003年   6278篇
  2002年   6060篇
  2001年   4666篇
  2000年   3827篇
  1999年   4158篇
  1998年   4444篇
  1997年   4172篇
  1996年   4033篇
  1995年   3828篇
  1994年   2548篇
  1993年   2113篇
  1992年   2064篇
  1991年   2080篇
  1990年   1622篇
  1989年   1732篇
  1988年   1525篇
  1987年   1362篇
  1986年   1396篇
  1985年   1338篇
  1984年   1201篇
  1983年   1047篇
  1982年   1165篇
  1981年   982篇
  1980年   880篇
  1979年   662篇
  1978年   717篇
  1977年   738篇
  1976年   528篇
  1975年   579篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
91.
92.
93.
94.
95.
96.
97.

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   
98.
99.
100.
Trabecular bone score (TBS) is used for fracture prediction in adults, but its utility in children is limited by absence of appropriate reference values. We aimed to develop reference ranges for TBS by age, sex, and population ancestry for youth ages 5 to 20 years. We also investigated the association between height, body mass index (BMI), and TBS, agreement between TBS and lumbar spine areal bone mineral density (aBMD) and bone mineral apparent density (BMAD) Z-scores, tracking of TBS Z-scores over time, and precision of TBS measurements. We performed secondary analysis of spine dual-energy X-ray absorptiometry (DXA) scans from the Bone Mineral Density in Childhood Study (BMDCS), a mixed longitudinal cohort of healthy children (n = 2014) evaluated at five US centers. TBS was derived using a dedicated TBS algorithm accounting for tissue thickness rather than BMI. TBS increased only during ages corresponding to pubertal development with an earlier increase in females than males. There were no differences in TBS between African Americans and non-African Americans. We provide sex-specific TBS reference ranges and LMS values for calculation of TBS Z-scores by age and means and SD for calculation of Z-scores by pubertal stage. TBS Z-scores were positively associated with height Z-scores at some ages. TBS Z-scores explained only 27% and 17% of the variance of spine aBMD and BMAD Z-scores. Tracking of TBS Z-scores over 6 years was lower (r = 0.47) than for aBMD or BMAD Z-scores (r = 0.74 to 0.79), and precision error of TBS (2.87%) was greater than for aBMD (0.85%) and BMAD (1.22%). In sum, TBS Z-scores provide information distinct from spine aBMD and BMAD Z-scores. Our robust reference ranges for TBS in a well-characterized pediatric cohort and precision error estimates provide essential tools for clinical assessment using TBS and determination of its value in predicting bone fragility in childhood and adolescence. © 2022 American Society for Bone and Mineral Research (ASBMR).  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