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   2703286篇
  免费   213010篇
  国内免费   7984篇
耳鼻咽喉   36871篇
儿科学   89580篇
妇产科学   75416篇
基础医学   377943篇
口腔科学   78476篇
临床医学   240655篇
内科学   534077篇
皮肤病学   62064篇
神经病学   222668篇
特种医学   110427篇
外国民族医学   740篇
外科学   415862篇
综合类   64416篇
现状与发展   5篇
一般理论   937篇
预防医学   211270篇
眼科学   61207篇
药学   196717篇
  8篇
中国医学   4876篇
肿瘤学   140065篇
  2018年   27267篇
  2016年   25261篇
  2015年   28783篇
  2014年   38997篇
  2013年   58854篇
  2012年   76640篇
  2011年   80820篇
  2010年   49079篇
  2009年   46736篇
  2008年   76720篇
  2007年   81716篇
  2006年   83187篇
  2005年   81255篇
  2004年   78755篇
  2003年   76112篇
  2002年   73407篇
  2001年   123724篇
  2000年   127463篇
  1999年   107468篇
  1998年   31414篇
  1997年   28278篇
  1996年   28764篇
  1995年   28318篇
  1994年   26616篇
  1993年   25005篇
  1992年   88339篇
  1991年   86102篇
  1990年   83409篇
  1989年   80181篇
  1988年   74538篇
  1987年   73423篇
  1986年   69517篇
  1985年   67202篇
  1984年   50972篇
  1983年   43411篇
  1982年   26488篇
  1981年   23806篇
  1980年   22452篇
  1979年   47718篇
  1978年   33973篇
  1977年   28727篇
  1976年   26704篇
  1975年   28350篇
  1974年   34021篇
  1973年   32656篇
  1972年   30185篇
  1971年   28239篇
  1970年   25892篇
  1969年   24319篇
  1968年   22444篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.

Objective

Low psoas muscle area is shown to be an indicator for worse postoperative outcome in patients undergoing vascular surgical. Additionally, it has been associated with longer durations of hospital stay in patients with cancer who undergo surgery and subsequently greater health care costs in Europe and the United States. We sought to evaluate this effect on hospital expenditure for patients undergoing vascular repair in a health care system with universal access.

Methods

Skeletal muscle mass was assessed on preoperative abdominal computed tomography scans of patients undergoing open aortic aneurysm repair in a retrospective fashion. The skeletal muscle index (SMI) was used to define low muscle mass. Health care costs were obtained for all patients and the relationship between a low SMI and higher costs was explored using linear regression and cross-sectional analysis.

Results

We included 156 patients (81.5% male) with a median age of 72 years undergoing elective surgery for infrarenal abdominal aortic aneurysm in this analysis. The median SMI for patients with low skeletal muscle mass was 53.21 cm2/kg and for patients without, 70.07 cm2/kg. Hospital duration of stay was 2 days longer in patients with low skeletal muscle mass as compared with patients with normal (14 days vs 11 days; P = .001), as was duration of intensive care stay (3 days vs 1 day; P = .01). The median overall hospital costs were €10,460 higher for patients with a low SMI as compared with patients with a normal physical constitution (€53,739 [interquartile range, €45,007-€62,471] vs €43,279 [interquartile range, €39,509-€47,049]; P = .001). After confounder adjustment, a low SMI was associated with a 14.68% cost increase in overall hospital costs, for a cost increase of €6521.

Conclusions

Low skeletal muscle mass is independently associated with higher hospital as well as intensive care costs in patients undergoing elective aortic aneurysm repair. Strategies to reduce this risk factor are warranted for these patients.  相似文献   
92.
93.
94.
95.
96.
97.
98.

Objectives

To investigate whether functional overreaching affects locomotor system behaviour when running at fixed relative intensities and if any effects were associated with changes in running performance.

Design

Prospective intervention study.

Methods

Ten trained male runners completed three training blocks in a fixed order. Training consisted of one week of light training (baseline), two weeks of heavy training designed to induce functional overreaching, and ten days of light taper training designed to allow athletes to recover from, and adapt to, the heavy training. Locomotor behaviour, 5-km time trial performance, and subjective reports of training status (Daily Analysis of Life Demands for Athletes (DALDA) questionnaire) were assessed at the completion of each training block. Locomotor behaviour was assessed using detrended fluctuation analysis of stride intervals during running at speeds corresponding to 65% and 85% of maximum heart rate (HRmax) at baseline.

Results

Time trial performance (effect size ±95% confidence interval (ES): 0.16 ± 0.06; p < 0.001), locomotor behaviour at 65% HRmax (ES: ?1.12 ± 0.95; p = 0.026), and DALDA (ES: 2.55 ± 0.80; p < 0.001) were all detrimentally affected by the heavy training. Time trial performance improved relative to baseline after the taper (ES: ?0.16 ± 0.10; p = 0.003) but locomotor behaviour at 65% HRmax (ES: ?1.18 ± 1.17; p = 0.048) and DALDA (ES: 0.92 ± 0.90; p = 0.045) remained impaired.

Conclusions

Locomotor behaviour during running at 65% HRmax was impaired by functional overreaching and remained impaired after a 10-day taper, despite improved running performance. Locomotor changes may increase injury risk and should be considered within athlete monitoring programs independently of performance changes.  相似文献   
99.

Introduction

Physician communication impacts patient outcomes. However, communication skills, especially around difficult conversations, remain suboptimal, and there is no clear way to determine the validity of entrustment decisions. The aims of this study were to 1) describe the development of a simulation-based mastery learning (SBML) curriculum for breaking bad news (BBN) conversation skills and 2) set a defensible minimum passing standard (MPS) to ensure uniform skill acquisition among learners.

Innovation

An SBML BBN curriculum was developed for fourth-year medical students. An assessment tool was created to evaluate the acquisition of skills involved in a BBN conversation. Pilot testing was completed to confirm improvement in skill acquisition and set the MPS.

Outcomes

A BBN assessment tool containing a 15-item checklist and six scaled items was developed. Students' checklist performance improved significantly at post-test compared to baseline (mean 65.33%, SD = 12.09% vs mean 88.67%, SD = 9.45%, P < 0.001). Students were also significantly more likely to have at least a score of 4 (on a five-point scale) for the six scaled questions at post-test. The MPS was set at 80%, requiring a score of 12 items on the checklist and at least 4 of 5 for each scaled item. Using the MPS, 30% of students would require additional training after post-testing.

Comments

We developed a SBML curriculum with a comprehensive assessment of BBN skills and a defensible competency standard. Future efforts will expand the mastery model to larger cohorts and assess the impact of rigorous education on patient care outcomes.  相似文献   
100.
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