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   4064972篇
  免费   307779篇
  国内免费   10192篇
耳鼻咽喉   57482篇
儿科学   130362篇
妇产科学   111153篇
基础医学   568663篇
口腔科学   116923篇
临床医学   374984篇
内科学   788541篇
皮肤病学   91249篇
神经病学   338031篇
特种医学   158582篇
外国民族医学   1438篇
外科学   610150篇
综合类   91155篇
现状与发展   6篇
一般理论   1721篇
预防医学   324978篇
眼科学   94653篇
药学   301334篇
  11篇
中国医学   7981篇
肿瘤学   213546篇
  2018年   43668篇
  2017年   33603篇
  2016年   38179篇
  2015年   43086篇
  2014年   60669篇
  2013年   92107篇
  2012年   122413篇
  2011年   129906篇
  2010年   77892篇
  2009年   74496篇
  2008年   121910篇
  2007年   129480篇
  2006年   131228篇
  2005年   126868篇
  2004年   122256篇
  2003年   117884篇
  2002年   114709篇
  2001年   187077篇
  2000年   192560篇
  1999年   163318篇
  1998年   48498篇
  1997年   43285篇
  1996年   42918篇
  1995年   41624篇
  1994年   38652篇
  1993年   36155篇
  1992年   129767篇
  1991年   125548篇
  1990年   121347篇
  1989年   117251篇
  1988年   108379篇
  1987年   106774篇
  1986年   100841篇
  1985年   96602篇
  1984年   72650篇
  1983年   62042篇
  1982年   37365篇
  1981年   33625篇
  1979年   66755篇
  1978年   47242篇
  1977年   40035篇
  1976年   37502篇
  1975年   39601篇
  1974年   48001篇
  1973年   45825篇
  1972年   43117篇
  1971年   39933篇
  1970年   37317篇
  1969年   35284篇
  1968年   32464篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
991.
The precise molecular cause of insulin resistance has not yet been elucidated. Resistance to the normal action of insulin contributes to the pathogenesis of a number of common human disorders, including type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetes mellitus, hypertension, and the Metabolic Syndrome X, thus constituting a major public health problem. A disease program aimed at combating this disorder should focus on the identification of targets for therapeutic intervention which may overcome insulin resistance and hence the associated metabolic consequences characteristic of the Metabolic Syndrome. Although the primary defect in the pathogenesis of type 2 diabetes is unknown, genetic and environmental factors are likely to contribute to the manifestation of this progressive metabolic disorder, which is usually not clinically apparent until mid-life. Defects at the level of glucose uptake/phosphorylation characterize insulin resistance in skeletal muscle of type 2 diabetic patients. Identification of putative components of the insulin receptor-signaling pathway may offer insights into mechanisms involved in insulin resistance. Enhanced flux of free fatty acids due to impaired lipid metabolism may contribute to impaired insulin secretion and peripheral insulin resistance. Genes regulating lipolysis are prime candidates for susceptibility towards the metabolic syndrome. Here we describe pathways constituting complex interactions that control glucose homeostasis. We will be considering (1) regulation of glucose uptake by the insulin receptor signaling pathway, and (2) control of adipogenesis and insulin sensitivity by the sterol response element binding protein (SREBP) pathway.  相似文献   
992.
Abstract: The current study examined the extent to which mothers, fathers, teachers, and teenage friends influenced Latino adolescents’ academic motivation. Using path analysis, separate models were tested for 154 Latino boys and 156 Latina girls. Findings indicated that mothers’ and teachers’ academic support were positively related to adolescent girls’ academic motivation, and fathers’ and teachers’ academic support were positively related to adolescent boys’ academic motivation. The salience of teachers’ support, possible reasons for gender differences, and implications for future research are discussed.  相似文献   
993.
Sugar and tooth decays are bound closely. The mechanisms of destruction of the tooth from the glycolyse are known. The role played by the food in the development of the caries is unique. Foods sweetened of all ways, rich in sucrose are responsible of the intervening of the carious lesions. The transformation of the fermentable sugars in lactic with the absence of hygiene and the action conjugated of the bacteria leads to tooth decays in temporary and permanent denture that evolve very quickly in the absence of treatment. Reasons for which the authors put in evidence in this survey, the influence of the food sweetened on the teeth at the children while showing the cases of caries and its complications due to the excessive consumption of fermentable hydrates of carbon.  相似文献   
994.
995.
996.
997.
The clinical presentation of electrical injury commonly involves physical, cognitive, and emotional complaints. Neuropsychological studies, including case reports, have indicated that electrical injury (EI) survivors may experience a broad range of impaired neuropsychological functions, although this has not been clarified through controlled investigation. In this study, we describe the neuropsychological test findings in a series of 29 EI patients carefully screened and matched to a group of 29 demographically similar healthy electricians. Participants were matched by their estimated premorbid intellectual ability. Multivariate analysis of variance was used to assess group differences in the following neuropsychological domains: attention and mental speed, working memory, verbal memory, visual memory, and motor skills. EI patients performed significantly worse on composite measures of attention/mental speed and motor skills, which could not be explained by demographic differences, injury parameters, litigation status, or mood disturbance. Results suggest that cognitive changes do occur in patients suffering from electrical injury.  相似文献   
998.
999.
1000.
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   
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