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   2594398篇
  免费   185421篇
  国内免费   7617篇
耳鼻咽喉   34361篇
儿科学   85359篇
妇产科学   71739篇
基础医学   364558篇
口腔科学   69821篇
临床医学   235091篇
内科学   517231篇
皮肤病学   62532篇
神经病学   214122篇
特种医学   100062篇
外国民族医学   736篇
外科学   387634篇
综合类   50432篇
现状与发展   5篇
一般理论   970篇
预防医学   196409篇
眼科学   56762篇
药学   188397篇
  8篇
中国医学   5344篇
肿瘤学   145863篇
  2021年   20205篇
  2019年   20798篇
  2018年   29456篇
  2017年   22704篇
  2016年   26399篇
  2015年   29714篇
  2014年   40747篇
  2013年   60750篇
  2012年   80738篇
  2011年   85039篇
  2010年   51325篇
  2009年   49411篇
  2008年   79510篇
  2007年   84384篇
  2006年   86013篇
  2005年   82163篇
  2004年   79155篇
  2003年   76415篇
  2002年   73652篇
  2001年   128451篇
  2000年   131362篇
  1999年   110549篇
  1998年   31314篇
  1997年   27974篇
  1996年   28267篇
  1995年   27436篇
  1994年   25119篇
  1993年   23461篇
  1992年   85195篇
  1991年   81589篇
  1990年   78800篇
  1989年   76080篇
  1988年   69479篇
  1987年   68010篇
  1986年   63561篇
  1985年   60528篇
  1984年   44961篇
  1983年   37961篇
  1982年   22468篇
  1981年   19993篇
  1979年   38964篇
  1978年   27443篇
  1977年   23256篇
  1976年   21499篇
  1975年   22820篇
  1974年   26791篇
  1973年   25370篇
  1972年   23751篇
  1971年   21957篇
  1970年   20185篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
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   
83.
84.
Imaging     
  相似文献   
85.
86.
87.
88.
89.
90.
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