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   2918534篇
  免费   200946篇
  国内免费   7861篇
耳鼻咽喉   38898篇
儿科学   95857篇
妇产科学   79637篇
基础医学   421021篇
口腔科学   78004篇
临床医学   265968篇
内科学   571885篇
皮肤病学   69774篇
神经病学   234002篇
特种医学   111848篇
外国民族医学   774篇
外科学   435413篇
综合类   55756篇
现状与发展   6篇
一般理论   1043篇
预防医学   221866篇
眼科学   64931篇
药学   213823篇
  9篇
中国医学   5961篇
肿瘤学   160865篇
  2019年   22804篇
  2018年   32503篇
  2017年   24907篇
  2016年   28957篇
  2015年   32527篇
  2014年   44540篇
  2013年   66636篇
  2012年   89397篇
  2011年   94995篇
  2010年   57107篇
  2009年   54330篇
  2008年   88465篇
  2007年   94339篇
  2006年   95785篇
  2005年   91606篇
  2004年   88289篇
  2003年   85416篇
  2002年   82413篇
  2001年   139987篇
  2000年   143250篇
  1999年   120593篇
  1998年   34348篇
  1997年   30423篇
  1996年   30706篇
  1995年   29665篇
  1994年   27183篇
  1993年   25589篇
  1992年   93396篇
  1991年   91038篇
  1990年   88388篇
  1989年   85587篇
  1988年   78395篇
  1987年   76854篇
  1986年   71895篇
  1985年   68736篇
  1984年   51031篇
  1983年   43133篇
  1982年   25149篇
  1981年   22526篇
  1979年   45099篇
  1978年   31824篇
  1977年   26802篇
  1976年   25353篇
  1975年   27466篇
  1974年   32084篇
  1973年   30494篇
  1972年   28510篇
  1971年   26583篇
  1970年   24558篇
  1969年   23547篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
BACKGROUND: Previous research has demonstrated that academic and neuropsychological functions are compromised in pediatric bipolar disorder (PBD). Investigation of the degree to which neuropsychological deficits might contribute to those academic problems is needed to aid in the recognition and intervention for school achievement difficulties in PBD. METHODS: A sample of 55 children and adolescents with PBD with and without attention-deficit/hyperactivity disorder (ADHD) (PBD group, n = 28; PBD+ADHD group, n = 27) were tested with a computerized neurocognitive battery and standardized neuropsychological tests. Age range of subjects was 7-17 years, with the mean age of 11.97 (3.18) years. Parents completed a structured questionnaire on school and academic functioning. RESULTS: Logistic regression analyses indicated that executive function, attention, working memory, and verbal memory scores were poorer in those with a history of reading/writing difficulties. A separate logistic regression analysis found that attentional dysfunction predicted math difficulties. These relationships between neuropsychological function and academic difficulties were not different in those with PBD+ADHD than in those with PBD alone. CONCLUSIONS: In PBD neuropsychological deficits in the areas of attention, working memory, and organization/problem solving skills all contribute to academic difficulties. Early identification and intervention for these difficulties might help prevent lower academic achievement in PBD.  相似文献   
102.
103.
Imaging     
  相似文献   
104.
105.
106.
107.
108.
109.
110.
Background: Few studies have examined the use of ultrasound for sciatic nerve localization. The authors evaluated the usefulness of low-frequency ultrasound in identifying the sciatic nerve at three locations in the lower extremity and in guiding needle advancement to target before nerve stimulation.

Methods: In this prospective observational study, 15 volunteers underwent sciatic nerve examination using a curved ultrasound probe in the range of 2-5 MHz and a Philips-ATL 5000 unit (ATL Ultrasound, Bothell, WA) in the gluteal, infragluteal, and proximal thigh regions. Thereafter, an insulated block needle was advanced inline with the ultrasound beam to reach the nerve target, which was further confirmed by electrical stimulation. The quality of sciatic nerve images, ease of needle to nerve contact, threshold stimulating current, and resultant motor response were recorded.

Results: The sciatic nerve was successfully identified in the transverse view as a solitary predominantly hyperechoic structure on ultrasound in all of the three regions examined. The target nerve was visualized easily in 87% and localized within two needle attempts in all patients. Nerve stimulation was successful in 100% after two attempts with a threshold current of 0.42 +/- 0.12 (mean +/- SD) eliciting foot plantarflexion or dorsiflexion.  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