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   1663篇
  免费   109篇
  国内免费   80篇
耳鼻咽喉   1篇
儿科学   57篇
妇产科学   27篇
基础医学   199篇
口腔科学   22篇
临床医学   220篇
内科学   286篇
皮肤病学   35篇
神经病学   82篇
特种医学   300篇
外科学   210篇
综合类   70篇
一般理论   1篇
预防医学   112篇
眼科学   36篇
药学   120篇
中国医学   3篇
肿瘤学   71篇
  2023年   7篇
  2022年   8篇
  2021年   18篇
  2020年   14篇
  2019年   17篇
  2018年   20篇
  2017年   18篇
  2016年   29篇
  2015年   19篇
  2014年   32篇
  2013年   50篇
  2012年   49篇
  2011年   45篇
  2010年   56篇
  2009年   63篇
  2008年   56篇
  2007年   102篇
  2006年   41篇
  2005年   50篇
  2004年   45篇
  2003年   33篇
  2002年   37篇
  2001年   33篇
  2000年   38篇
  1999年   45篇
  1998年   74篇
  1997年   86篇
  1996年   59篇
  1995年   74篇
  1994年   40篇
  1993年   42篇
  1992年   32篇
  1991年   34篇
  1990年   27篇
  1989年   51篇
  1988年   42篇
  1987年   34篇
  1986年   38篇
  1985年   55篇
  1984年   27篇
  1983年   19篇
  1982年   29篇
  1981年   16篇
  1980年   27篇
  1979年   9篇
  1978年   9篇
  1977年   19篇
  1976年   20篇
  1975年   12篇
  1969年   7篇
排序方式: 共有1852条查询结果,搜索用时 15 毫秒
1.

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   
2.
Coronary artery bypass grafts: visualization with MR imaging   总被引:1,自引:0,他引:1  
Gomes  AS; Lois  JF; Drinkwater  DC  Jr; Corday  SR 《Radiology》1987,162(1):175
  相似文献   
3.
Summary— The influence of local resistance and cardiac performance on peripheral blood acceleration was investigated in 14 healthy male volunteers. Steady and pulsatile flow was studied in the brachial and in the common carotid arteries, ie, two territories that exhibit marked differences in resistive characteristics. Instantaneous blood velocity (V), mean blood velocity (Vm) and artery diameter (D) were evaluated at rest by an ultrasonic range-gated pulsed Doppler flowmeter using a double transducer probe, thus allowing the calculation of mean blood flow (Q). Mean local resistance (R) was obtained by dividing the mean arterial pressure by Q. The peak value of the local acceleration of the blood was obtained by computer-assisted calculation of the first derivative of instantaneous blood velocity (Gmax = +dV/dtmax). Peak aortic blood acceleration (GAo) was simultaneously measured from the suprasternal notch using a pulsed Doppler velocity meter. In the brachial and the common carotid arteries, Gmax was of a similar magnitude (551 ±30 and 555 ± 44 cm/s2, respectively) despite major differences in the respective D, Vm, Q and R values. In neither artery was there a relationship between Gmax and either resting Q or R. At the brachial artery level, Gmax was positively related to GAo ( r = 0.79, P = 0.0008). At the common carotid artery level, there was a weak, although non significant relationship between Gmax and GAo ( P = 0.08). Our results indicate that the local acceleration of peripheral blood flow in the brachial artery is related rather to upstream central impulse than to downstream hemodynamics, and suggest some regional differences in the hemodynamic determinants of the local acceleration of peripheral blood flow.  相似文献   
4.
The striated urethral sphincter is the predominant muscular structure divided posteriorly during the apical dissection in radical prostatectomy. The authors have long realized the value of this maneuver in obtaining excellent apical surgical margins and in identifying the correct plane on the anterior surface of the rectum. Recently, they also have recognized the importance of incorporating this musculature into the vesicourethral anastomosis to fix the bladder neck and thus re-establish anatomic continuity. Identification of the striated urethral sphincter ranks in importance with elucidation of the anatomy of the dorsal vein complex and the anatomic identification of the neurovascular bundle in improving the patient's quality of life postoperatively.  相似文献   
5.
J K Burgers  D M Quinlan  C B Brendler 《The Journal of urology》1990,144(5):1188-90; discussion 1190-1
Creation of a circumferentially protruding urinary intestinal stoma is an important aspect to prevent stomal regression, stenosis and parastomal herniation. Furthermore, an improperly fashioned stoma may make fitting of an ostomy appliance difficult, resulting in urinary leakage with secondary dermatitis and incrustation. The major difficulty in fashioning the stoma is everting the mucosa over the intestinal mesentery. We describe our method of stoma formation that creates a circumferentially symmetrical protruding stoma free of tension that has been used successfully even in obese patients. This technique has made the use of a Turnbull stoma unnecessary in our recent experience.  相似文献   
6.
7.
8.
PURPOSE: To profile adolescent Internet chat room users in terms of demographic characteristics, psychological and environmental factors, and behavioral risk factors. METHODS: The study sample was drawn from respondents to an anonymous statewide survey of 50,168 9th-grade public school students and included 40,376 students who reported Internet access at home and 19,511 who accessed chat rooms. Data were collected by the Minnesota Student Survey (MSS), a survey that has been administered triennially by the state's education department to public school students in grades 6, 9, and 12 since 1989. The MSS includes more than 117 questions (300 variables) addressing attitudinal, behavioral, and environmental issues. Data analysis consisted of comparing the odds of a particular characteristic or behavior for chat room users with that of nonusers. Analyses were run separately for boys and girls. The homogeneity of odd ratios was tested with the Breslow-Day statistic using SPSS for Windows. RESULTS: For boys and girls, use of Internet chat rooms was associated with psychological distress, a difficult living environment, and a higher likelihood of risky behaviors. Although most chat room users did not report serious problems, this group included a disproportionate number of troubled individuals. CONCLUSIONS: Because chat room use serves as an indicator of heightened vulnerability and risk-taking, parents and others need to be aware of potential dangers posed by online contact between strangers and youth.  相似文献   
9.
10.
Intestinal obstruction proximal to a transition zone without an interposed physical barrier usually indicates Hirschsprung disease. The authors report one case of focal small bowel muscular thinning just distal to a transition zone that produced clinical and radiographic findings that simulated long-segment Hirschsprung disease in a 2-day-old infant.  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