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   2580220篇
  免费   179950篇
  国内免费   4013篇
耳鼻咽喉   34149篇
儿科学   85095篇
妇产科学   71258篇
基础医学   370897篇
口腔科学   69012篇
临床医学   229133篇
内科学   499314篇
皮肤病学   51663篇
神经病学   209358篇
特种医学   100706篇
外国民族医学   608篇
外科学   386763篇
综合类   52434篇
现状与发展   6篇
一般理论   956篇
预防医学   206189篇
眼科学   57548篇
药学   189491篇
  8篇
中国医学   4920篇
肿瘤学   144675篇
  2018年   46089篇
  2017年   35980篇
  2016年   40928篇
  2015年   25989篇
  2014年   35600篇
  2013年   53248篇
  2012年   78940篇
  2011年   97044篇
  2010年   62391篇
  2009年   54097篇
  2008年   92575篇
  2007年   100869篇
  2006年   79912篇
  2005年   80518篇
  2004年   79022篇
  2003年   77404篇
  2002年   73456篇
  2001年   101801篇
  2000年   104202篇
  1999年   88566篇
  1998年   26978篇
  1997年   24145篇
  1996年   24218篇
  1995年   22975篇
  1994年   21619篇
  1993年   20067篇
  1992年   70789篇
  1991年   69904篇
  1990年   68541篇
  1989年   66354篇
  1988年   61794篇
  1987年   60703篇
  1986年   57856篇
  1985年   55141篇
  1984年   41754篇
  1983年   36369篇
  1982年   22172篇
  1981年   19923篇
  1979年   39862篇
  1978年   28725篇
  1977年   24443篇
  1976年   22921篇
  1975年   24864篇
  1974年   29713篇
  1973年   28888篇
  1972年   27397篇
  1971年   25519篇
  1970年   23940篇
  1969年   22853篇
  1968年   21414篇
排序方式: 共有10000条查询结果,搜索用时 968 毫秒
61.

Introduction

Several studies demonstrated that simulator-acquired skill transfer to the operating room is incomplete. Our objective was to identify trainee characteristics that predict the transfer of simulator-acquired skill to the operating room.

Methods

Trainees completed baseline assessments including intracorporeal suturing (IS) performance, attentional selectivity, self-reported use of mental skills, and self-reported prior clinical and simulated laparoscopic experience and confidence. Residents then followed proficiency-based laparoscopic skills training, and their skill transfer was assessed on a live-anesthetized porcine model. Predictive characteristics for transfer test performance were assessed using multiple linear regression.

Results

Thirty-eight residents completed the study. Automaticity, attentional selectivity, resident perceived ability with laparoscopy and simulators, and post-training IS performance were predictive of IS performance during the transfer test.

Conclusions

Promoting automaticity, self-efficacy, and attention selectivity may help improve the transfer of simulator-acquired skill. Mental skills training and training to automaticity may therefore be valuable interventions to achieve this goal.  相似文献   
62.
63.
64.
65.
66.
67.
68.
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.  相似文献   
69.
Pediatric trachyonychia is an acquired nail disease that can cause distress to families. It is a poorly understood disease, and long‐term follow‐up data are lacking. We present an institutional review of 11 children with isolated pediatric trachyonychia followed over time. Children with the diagnosis of pediatric trachyonychia were identified and invited to participate. Pictures were taken on follow‐up and a questionnaire was answered. Exclusion criteria include having another diagnosis at the initial visit that causes nail dystrophy. Eleven patients with the diagnosis of pediatric trachyonychia were available for follow‐up. The mean age of appearance was 2.7 years (range 2–7 yrs) and the average follow‐up was 66 months (range 10–126 mos). Nine patients were treated with potent topical corticosteroids, one used only petrolatum, and one took vitamin supplements. One patient was found to have an additional skin and hair diagnosis of alopecia areata on follow‐up. On follow‐up, 82% noted improvement of the nails, whereas 18% noted no change. A majority of cases of pediatric trachyonychia are isolated and improve with time, regardless of treatment.  相似文献   
70.
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