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   3152059篇
  免费   228945篇
  国内免费   8757篇
耳鼻咽喉   43692篇
儿科学   101764篇
妇产科学   88224篇
基础医学   444424篇
口腔科学   88269篇
临床医学   284917篇
内科学   616061篇
皮肤病学   73568篇
神经病学   258040篇
特种医学   122103篇
外国民族医学   884篇
外科学   475202篇
综合类   68959篇
现状与发展   7篇
一般理论   1159篇
预防医学   242861篇
眼科学   71609篇
药学   231410篇
  8篇
中国医学   6391篇
肿瘤学   170209篇
  2018年   33608篇
  2017年   25908篇
  2016年   29965篇
  2015年   33994篇
  2014年   47092篇
  2013年   71101篇
  2012年   94128篇
  2011年   99440篇
  2010年   59800篇
  2009年   57240篇
  2008年   93048篇
  2007年   99289篇
  2006年   100791篇
  2005年   96984篇
  2004年   93733篇
  2003年   90709篇
  2002年   87370篇
  2001年   147264篇
  2000年   150624篇
  1999年   127301篇
  1998年   37113篇
  1997年   33146篇
  1996年   33142篇
  1995年   32015篇
  1994年   29547篇
  1993年   27732篇
  1992年   100620篇
  1991年   97076篇
  1990年   94281篇
  1989年   91136篇
  1988年   83788篇
  1987年   82326篇
  1986年   77384篇
  1985年   74038篇
  1984年   55609篇
  1983年   47357篇
  1982年   28545篇
  1981年   25692篇
  1979年   50695篇
  1978年   36162篇
  1977年   30642篇
  1976年   28364篇
  1975年   30400篇
  1974年   36318篇
  1973年   34623篇
  1972年   32660篇
  1971年   30274篇
  1970年   28165篇
  1969年   27171篇
  1968年   24914篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
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   
103.
104.
Imaging     
  相似文献   
105.
106.
107.
108.
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   
109.
110.
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