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   3255200篇
  免费   240361篇
  国内免费   5703篇
耳鼻咽喉   44755篇
儿科学   106329篇
妇产科学   89792篇
基础医学   474151篇
口腔科学   89860篇
临床医学   296244篇
内科学   627910篇
皮肤病学   73009篇
神经病学   260379篇
特种医学   121796篇
外国民族医学   905篇
外科学   488047篇
综合类   72149篇
现状与发展   15篇
一般理论   1199篇
预防医学   257502篇
眼科学   75874篇
药学   238889篇
  11篇
中国医学   6864篇
肿瘤学   175584篇
  2021年   25821篇
  2019年   26649篇
  2018年   36978篇
  2017年   27832篇
  2016年   31430篇
  2015年   35290篇
  2014年   50113篇
  2013年   75228篇
  2012年   102981篇
  2011年   109968篇
  2010年   65100篇
  2009年   61638篇
  2008年   102386篇
  2007年   108880篇
  2006年   110021篇
  2005年   106790篇
  2004年   102348篇
  2003年   98134篇
  2002年   94794篇
  2001年   150378篇
  2000年   154142篇
  1999年   129273篇
  1998年   37802篇
  1997年   33463篇
  1996年   33510篇
  1995年   31659篇
  1994年   29200篇
  1993年   27428篇
  1992年   99478篇
  1991年   96600篇
  1990年   93917篇
  1989年   90469篇
  1988年   83308篇
  1987年   81326篇
  1986年   76271篇
  1985年   73188篇
  1984年   54953篇
  1983年   46697篇
  1982年   28126篇
  1979年   50118篇
  1978年   35589篇
  1977年   29646篇
  1976年   28272篇
  1975年   30015篇
  1974年   36256篇
  1973年   34541篇
  1972年   32549篇
  1971年   30484篇
  1970年   28358篇
  1969年   26815篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
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   
112.
113.
114.
115.
116.
117.
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   

118.
119.
120.
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