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   2010759篇
  免费   164565篇
  国内免费   7698篇
耳鼻咽喉   27316篇
儿科学   62548篇
妇产科学   56461篇
基础医学   280608篇
口腔科学   57054篇
临床医学   179929篇
内科学   401992篇
皮肤病学   45466篇
神经病学   164889篇
特种医学   82029篇
外国民族医学   431篇
外科学   314784篇
综合类   51384篇
现状与发展   4篇
一般理论   653篇
预防医学   160739篇
眼科学   45193篇
药学   144013篇
  5篇
中国医学   3542篇
肿瘤学   103982篇
  2018年   19259篇
  2016年   17956篇
  2015年   20432篇
  2014年   28747篇
  2013年   43323篇
  2012年   54672篇
  2011年   58328篇
  2010年   35729篇
  2009年   34511篇
  2008年   54773篇
  2007年   58890篇
  2006年   59784篇
  2005年   58089篇
  2004年   56012篇
  2003年   54315篇
  2002年   51747篇
  2001年   90932篇
  2000年   93338篇
  1999年   78357篇
  1998年   23971篇
  1997年   21589篇
  1996年   22305篇
  1995年   21998篇
  1994年   20695篇
  1993年   19492篇
  1992年   65779篇
  1991年   64259篇
  1990年   62175篇
  1989年   59405篇
  1988年   55431篇
  1987年   54605篇
  1986年   51575篇
  1985年   49975篇
  1984年   38409篇
  1983年   32542篇
  1982年   20575篇
  1981年   18723篇
  1980年   17626篇
  1979年   36364篇
  1978年   26346篇
  1977年   22236篇
  1976年   20415篇
  1975年   21730篇
  1974年   26152篇
  1973年   25042篇
  1972年   23520篇
  1971年   21649篇
  1970年   20222篇
  1969年   19285篇
  1968年   17702篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
63.
64.
Imaging     
  相似文献   
65.
66.
67.
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   
68.
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   

69.
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   
70.
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