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   51309篇
  免费   3865篇
  国内免费   114篇
耳鼻咽喉   494篇
儿科学   1861篇
妇产科学   1366篇
基础医学   6324篇
口腔科学   476篇
临床医学   6553篇
内科学   9216篇
皮肤病学   1016篇
神经病学   5131篇
特种医学   1030篇
外科学   5465篇
综合类   450篇
现状与发展   1篇
一般理论   90篇
预防医学   7283篇
眼科学   966篇
药学   3553篇
中国医学   60篇
肿瘤学   3953篇
  2024年   58篇
  2023年   519篇
  2022年   837篇
  2021年   1860篇
  2020年   1120篇
  2019年   1836篇
  2018年   1941篇
  2017年   1486篇
  2016年   1577篇
  2015年   1662篇
  2014年   2340篇
  2013年   3062篇
  2012年   4563篇
  2011年   4506篇
  2010年   2478篇
  2009年   2056篇
  2008年   3544篇
  2007年   3481篇
  2006年   3255篇
  2005年   3037篇
  2004年   2623篇
  2003年   2209篇
  2002年   1951篇
  2001年   264篇
  2000年   212篇
  1999年   282篇
  1998年   319篇
  1997年   232篇
  1996年   193篇
  1995年   177篇
  1994年   123篇
  1993年   114篇
  1992年   104篇
  1991年   90篇
  1990年   88篇
  1989年   83篇
  1988年   61篇
  1987年   52篇
  1986年   52篇
  1985年   47篇
  1984年   72篇
  1983年   90篇
  1982年   64篇
  1981年   62篇
  1980年   76篇
  1979年   44篇
  1978年   50篇
  1977年   41篇
  1976年   33篇
  1973年   34篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
Unfortunately, acute pulmonary embolism is still a far too common occurrence. Fortunately, with prompt recognition, diagnosis, and treatment, mortality can be reduced. This article provides an overview of risk factors, diagnostic studies, and treatment of patients with acute pulmonary embolism in the critical care setting.  相似文献   
104.
105.
Shape and letter cancellation test performance was investigated among large samples of African American, Hispanic, and White non-demented elders. Ethnic minority elders took significantly longer to complete both tasks compared to Whites. An index of task efficiency, which simultaneously measures time and accuracy, suggested that slower time by minority elders was not related to a measurable effort to achieve greater accuracy. The frequency of commission errors was greater in our sample than in previous reports, especially among ethnic minority elders. Although significant differences were observed between the ethnic groups when matched for years of education, equating for literacy level eliminated all performance differences between African Americans and Whites on both cancellation tasks.  相似文献   
106.
107.
To increase preschoolers' science and mathematics learning experiences both within and outside the classroom, we developed age-appropriate materials containing general questions and instructions that teachers and parents could use when interacting with their students and children. The questions and instructions were related to a specific science or mathematics skill (e.g., classifying), but were general enough so that they could be applied to a variety of situations. Observations of three classrooms and interviews with the classroom teachers and aides, and the parents of the children in the classrooms suggested that use of these materials was beneficial to the children, teachers, and parents, and resulted in increasing the amount of science and mathematics activities and discussions in two of the classrooms as well as outside the classrooms.  相似文献   
108.
BACKGROUND: Abnormalities in the limbic-hypothalamic-pituitary-adrenal (LHPA) axis have been implicated in the pathogenesis of obsessive-compulsive disorder (OCD). To our knowledge, however, no prior study has measured pituitary gland volume in OCD. METHODS: Volumetric magnetic resonance imaging studies were conducted in 31 psychotropic drug-na?ve children (10 boys, 21 girls) aged 8-17 years and 31 case-matched healthy comparison subjects. RESULTS: Pituitary volume was significantly smaller in patients with OCD as compared with healthy control subjects (11% smaller). Smaller pituitary volume in patients with OCD was associated with increased compulsive but not obsessive symptom severity. Boys with OCD had smaller pituitary gland volumes compared with control boys (20% smaller). No significant differences in pituitary volume were observed between girls with OCD and control girls. Boys with OCD had significantly smaller pituitary volumes than girls with OCD (31% smaller), whereas control boys also had smaller pituitary gland volumes compared with control girls (21% smaller). CONCLUSIONS: These findings provide new evidence of reduced pituitary volume in pediatric OCD that seems to be more prominent in male patients. The observed alterations in pituitary volume are consistent with neuroendocrine studies that have reported abnormalities in the LHPA axis in OCD.  相似文献   
109.
110.
A large proportion of stroke survivors have to deal with problems in mobility. Proper evaluations must be undertaken to understand the sensorimotor impairments underlying locomotor disorders post stroke, so that evidence-based interventions can be developed. The current electrophysiological, biomechanical, and imagery evaluations that provide insight into locomotor dysfunction post stroke, as well as their advantages and limitations, are reviewed in this paper. In particular, electrophysiological evaluations focus on the contrast of electromyographic patterns and integrity of spinal reflex pathways during perturbed and unperturbed locomotion between persons with stroke and healthy individuals. At a behavioral level, biomechanical evaluations that include temporal distance factors, kinematic and kinetic analyses, as well as the mechanical energy and metabolic cost, are useful when combined with electrophysiological measures for the interpretation of gait disturbances that are related to the control of the central nervous system or secondary to biomechanical constraints. Finally, current methods in imaging and transcranial magnetic stimulation can provide further insight into cortical control of locomotion and the integrity of the corticospinal pathways.  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