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   2587316篇
  免费   185060篇
  国内免费   7569篇
耳鼻咽喉   34272篇
儿科学   85196篇
妇产科学   71568篇
基础医学   363577篇
口腔科学   69658篇
临床医学   234492篇
内科学   515539篇
皮肤病学   62450篇
神经病学   213440篇
特种医学   99876篇
外国民族医学   736篇
外科学   386405篇
综合类   50391篇
现状与发展   5篇
一般理论   968篇
预防医学   196164篇
眼科学   56663篇
药学   187983篇
  8篇
中国医学   5331篇
肿瘤学   145223篇
  2021年   19982篇
  2019年   20626篇
  2018年   29286篇
  2017年   22591篇
  2016年   26223篇
  2015年   29499篇
  2014年   40439篇
  2013年   60422篇
  2012年   80218篇
  2011年   84484篇
  2010年   51000篇
  2009年   49145篇
  2008年   79025篇
  2007年   83832篇
  2006年   85563篇
  2005年   81726篇
  2004年   78721篇
  2003年   76039篇
  2002年   73333篇
  2001年   128408篇
  2000年   131330篇
  1999年   110498篇
  1998年   31252篇
  1997年   27919篇
  1996年   28218篇
  1995年   27383篇
  1994年   25067篇
  1993年   23419篇
  1992年   85160篇
  1991年   81563篇
  1990年   78783篇
  1989年   76059篇
  1988年   69468篇
  1987年   67996篇
  1986年   63542篇
  1985年   60510篇
  1984年   44940篇
  1983年   37943篇
  1982年   22456篇
  1981年   19984篇
  1979年   38959篇
  1978年   27439篇
  1977年   23252篇
  1976年   21495篇
  1975年   22813篇
  1974年   26786篇
  1973年   25370篇
  1972年   23749篇
  1971年   21955篇
  1970年   20183篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
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   
82.
83.
Imaging     
  相似文献   
84.
85.
86.
87.
88.
89.
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   

90.
Infections due to Penicillium species other than P.marneffei are rare. We identified a boy with X-linked chronic granulomatous disease (X-CGD) with a pulmonary nodule and adjacent rib osteomyelitis caused by Penicillium piceum. The only sign of infection was an elevated sedimentation rate. P. piceum was isolated by fine needle aspirate and from excised infected tissues. Surgical removal and one year of voriconazole treatment were very well tolerated and led to complete recovery. Microbiological, microscopic and molecular studies support the fungal diagnosis. P. piceum should be considered as a relevant pathogen in immunocompromised patients.  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