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   29618篇
  免费   1417篇
  国内免费   195篇
耳鼻咽喉   324篇
儿科学   548篇
妇产科学   704篇
基础医学   3410篇
口腔科学   1527篇
临床医学   2254篇
内科学   7972篇
皮肤病学   443篇
神经病学   2733篇
特种医学   1246篇
外科学   4276篇
综合类   112篇
一般理论   7篇
预防医学   1555篇
眼科学   433篇
药学   1628篇
中国医学   119篇
肿瘤学   1939篇
  2023年   175篇
  2022年   418篇
  2021年   803篇
  2020年   457篇
  2019年   632篇
  2018年   820篇
  2017年   574篇
  2016年   697篇
  2015年   804篇
  2014年   1109篇
  2013年   1496篇
  2012年   2283篇
  2011年   2461篇
  2010年   1415篇
  2009年   1252篇
  2008年   2135篇
  2007年   2189篇
  2006年   2023篇
  2005年   2028篇
  2004年   1802篇
  2003年   1558篇
  2002年   1451篇
  2001年   194篇
  2000年   121篇
  1999年   175篇
  1998年   242篇
  1997年   194篇
  1996年   188篇
  1995年   145篇
  1994年   132篇
  1993年   93篇
  1992年   101篇
  1991年   97篇
  1990年   83篇
  1989年   85篇
  1988年   81篇
  1987年   59篇
  1986年   58篇
  1985年   48篇
  1984年   87篇
  1983年   63篇
  1982年   73篇
  1981年   48篇
  1980年   28篇
  1979年   35篇
  1978年   28篇
  1977年   31篇
  1976年   22篇
  1974年   16篇
  1973年   22篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
It has been hypothesized that freezing of gait (FOG) in parkinsonian patients (PD) might be triggered by a breakdown in the normal symmetry of gait. In this study, we evaluated the relationship between asymmetry of gait and FOG and the effects of intensive treadmill treatment on asymmetry. We studied 30 patients with (FOG+) and 30 without (FOG?) freezing in “on” stage. Patients underwent a 4-week rehabilitation treatment using a treadmill with auditory and visual cues and were evaluated at enrolment and at the end of rehabilitation. Outcome measures were gait speed, stride length, asymmetry of gait, Six-minute walking test (6MWT), Unified Parkinson’s Disease Rating Scale (UPDRS) II–III, Berg Balance Scale, Timed Up and Go Test, comfortable-fast gait speeds, freezing of gait questionnaire (FOGQ). At enrolment, no differences in gait parameters were observed between the two groups, which differed only in UPDRS_II and BBS. Both FOG+ and FOG? patients spent more time on the left foot (time on left/time on right foot 1.37, p = 0.002, 1.18, p = 0.016, respectively). Rehabilitation determined a homogeneous improvement in both groups of patients for all variables except UPDRS_II and balance, for which a better improvement was observed in FOG+ patients. The improvement in FOGQ in FOG+ patients was significantly correlated to the improvement in asymmetry of gait (Spearman R = 0.46, p = 0.013). Our data support a direct involvement of the asymmetry of gait in the development of FOG in PD. Treadmill training is effective in improving gait and balance in PD FOG+ patients and this might be related to a reduction of asymmetric gait.  相似文献   
993.
Unilateral spatial neglect is a common consequence of stroke that directly affects the performance of activities of daily living. This impairment is traditionally assessed with paper-and-pencil tests that can lack correspondence to real life and are easily compensated. Virtual reality can immerse patients in more ecological scenarios, thus providing therapists with new tools to assess and train the effects of this impairment in simulated real tasks. This paper presents the clinical validation and convergent validity of a low-cost virtual reality system for training street-crossing in stroke patients with and without neglect. The performance of neglect patients was significantly worse than the performance of non-neglect and healthy participants. In addition, several correlations between the scores in the system and in the traditional scales were detected.  相似文献   
994.
995.
996.
997.
Individuals with schizophrenia experience problems in the perception of emotion throughout the course of the disorder. Few studies have addressed the progression of the deficit over time. The present investigation explores face emotion recognition (FER) performance throughout the course of schizophrenia. The aim of the study was to test the hypotheses that: 1) FER impairment was present in ultra high-risk (putatively prodromal) individuals, and that 2) impairment was stable across the course of the illness. Forty-three individuals with a putative prodromal syndrome, 50 patients with first episode of schizophrenia, 44 patients with multi-episode schizophrenia and 86 unaffected healthy control subjects were assessed to examine emotion recognition ability. ANCOVA analysis adjusted for possible confounder factors and subsequent planned contrasts with healthy controls was undertaken. The results revealed deficits in recognition of sadness and disgust in prodromal individuals, and of all negative emotions in both first-episode and multi-episode patients. Furthermore, there were no significant differences between clinical groups. Within the framework of the neurodevelopmental model of schizophrenia, our results suggest the presence of emotional recognition impairment before the onset of full-blown psychosis. Moreover, the deficit remains stable over the course of illness, fitting the pattern of a vulnerability indicator in contrast to an indicator of chronicity or severity.  相似文献   
998.
999.
The purpose of this study was to retrospectively compare the treatment times of Class II division 1 malocclusion subjects treated with four first premolar extractions or a non-extraction protocol and fixed edgewise appliances. Eighty-four patients were selected and divided into two groups. Group 1, treated with four first premolar extractions, consisted of 48 patients (27 males and 21 females) with a mean age of 13.03 years and group 2, treated without extractions, consisted of 36 patients (18 males and 18 females) with a mean age of 13.13 years. Group 2 was subdivided into two subgroups, 2A consisting of 16 patients treated in one phase and 2B consisting of 20 patients treated in two phases. The initial and final Treatment Priority Index (TPI), initial ages, initial mandibular crowding, and treatment times of groups 1 and 2 were compared with t-tests. These variables were also compared between group 1 and the subgroups with analysis of variance followed by Tukey's tests. The treatment times for groups 1 and 2 and subgroups 2A and 2B were 2.36, 2.47, 2.25, and 2.64 years, respectively, which were not significantly different. Treatment times with non-extraction and four premolar extraction protocols are similar.  相似文献   
1000.
This study evaluated factors that may influence the presence or absence of interproximal papillae. Clinical evaluation consisted of visual determination, and quantitative analyses were made using millimeter grids on radiographs. Patients (n = 45) were divided into three groups according to age. Data were analyzed using the chi-square test followed by the Student t test (α = .05). The distance from the contact point to the bone crest had significant influence on papilla presence in both anterior and posterior sites (P < .05), whereas the width between roots of adjacent teeth did not. The papilla was missing more frequently in anterior sites. The presence of papillae was not age-dependent.  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