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   1827910篇
  免费   150870篇
  国内免费   5916篇
耳鼻咽喉   26297篇
儿科学   60322篇
妇产科学   48253篇
基础医学   243915篇
口腔科学   50155篇
临床医学   175323篇
内科学   374426篇
皮肤病学   45480篇
神经病学   144182篇
特种医学   69560篇
外国民族医学   242篇
外科学   293276篇
综合类   39189篇
现状与发展   75篇
一般理论   532篇
预防医学   130404篇
眼科学   43245篇
药学   124442篇
  8篇
中国医学   4489篇
肿瘤学   110881篇
  2021年   15389篇
  2020年   13236篇
  2019年   15327篇
  2018年   26393篇
  2017年   21686篇
  2016年   23982篇
  2015年   26254篇
  2014年   39824篇
  2013年   51652篇
  2012年   57541篇
  2011年   60227篇
  2010年   41968篇
  2009年   43375篇
  2008年   56659篇
  2007年   58330篇
  2006年   60983篇
  2005年   55804篇
  2004年   53386篇
  2003年   49892篇
  2002年   48203篇
  2001年   95149篇
  2000年   96294篇
  1999年   79821篇
  1998年   22974篇
  1997年   20332篇
  1996年   20333篇
  1995年   19532篇
  1994年   16949篇
  1993年   15429篇
  1992年   58561篇
  1991年   56491篇
  1990年   53903篇
  1989年   51777篇
  1988年   47024篇
  1987年   45670篇
  1986年   43005篇
  1985年   40605篇
  1984年   29823篇
  1983年   25362篇
  1982年   14336篇
  1979年   25794篇
  1978年   17873篇
  1977年   15248篇
  1976年   14081篇
  1975年   14802篇
  1974年   17831篇
  1973年   17147篇
  1972年   15947篇
  1971年   14633篇
  1970年   13651篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
BACKGROUND: The aim of this study was to estimate the cost effectiveness of screening for abdominal aortic aneurysm (AAA). MATERIAL AND METHODS: All 12,639 men born in the years 1921-1933 (aged 64-73) living in Viborg County, Denmark, were randomly allocated either to receive an invitation to abdominal ultrasound scanning for AAA or to be controls. Costs for screening and surveillance were assessed prospectively. Diagnosis Related Group (DRG) costs from 1999 were used concerning admissions with uncomplicated and complicated operations. Admissions for AAA surgery were retrospectively classified according to complications in patient records. RESULTS: Mean follow-up time was 52 months. 76.6% of invited men attended screening, and 191 (4.0%) had an AAA. As previously reported, the cumulative 5-year AAA-specific mortality in the invited group was significantly reduced by 67% compared to the control group (P = 0.003). The costs were estimated to be Euro 11.23 per scan. The costs per life-year saved were Euro 9057 (Euro 5872-20,063) after 5 years, and were expected to decrease to Euro 2708 (Euro 1758-6031) after 10 years and to Euro 1825 (Euro 1185-4063) after 15 years. CONCLUSION: Screening of 64-73 years old males in Denmark seems cost effective.  相似文献   
74.
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   

75.
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   
76.
77.
78.
79.
80.
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