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   2726篇
  免费   185篇
  国内免费   11篇
耳鼻咽喉   12篇
儿科学   189篇
妇产科学   66篇
基础医学   405篇
口腔科学   116篇
临床医学   285篇
内科学   488篇
皮肤病学   122篇
神经病学   250篇
特种医学   72篇
外科学   302篇
综合类   15篇
一般理论   3篇
预防医学   220篇
眼科学   22篇
药学   202篇
中国医学   4篇
肿瘤学   149篇
  2023年   16篇
  2022年   29篇
  2021年   58篇
  2020年   44篇
  2019年   59篇
  2018年   72篇
  2017年   58篇
  2016年   81篇
  2015年   64篇
  2014年   113篇
  2013年   152篇
  2012年   178篇
  2011年   190篇
  2010年   105篇
  2009年   93篇
  2008年   177篇
  2007年   195篇
  2006年   177篇
  2005年   154篇
  2004年   170篇
  2003年   130篇
  2002年   148篇
  2001年   27篇
  2000年   27篇
  1999年   28篇
  1998年   22篇
  1997年   34篇
  1996年   25篇
  1995年   35篇
  1994年   23篇
  1993年   21篇
  1992年   27篇
  1991年   13篇
  1990年   12篇
  1989年   11篇
  1988年   5篇
  1987年   5篇
  1986年   12篇
  1985年   6篇
  1984年   21篇
  1983年   16篇
  1982年   14篇
  1981年   8篇
  1980年   5篇
  1979年   14篇
  1977年   7篇
  1974年   4篇
  1973年   5篇
  1967年   6篇
  1965年   3篇
排序方式: 共有2922条查询结果,搜索用时 15 毫秒
31.
Prevention Science - The long-term sustainment of bullying prevention programs has rarely been investigated. This study addresses this gap by identifying facilitators and barriers to the systematic...  相似文献   
32.
Our aim was to study the associations between maternal vitamin C and iron intake during pregnancy and the offspring’s risk of developing islet autoimmunity and type 1 diabetes. The study was a part of the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) prospective birth cohort including children genetically at risk of type 1 diabetes born between 1997–2004. The diets of 4879 mothers in late pregnancy were assessed with a validated food frequency questionnaire. The outcomes were islet autoimmunity and type 1 diabetes. Cox proportional hazards regression analysis adjusted for energy, family history of diabetes, human leukocyte antigen (HLA) genotype and sex was used for statistical analyses. Total intake of vitamin C or iron from food and supplements was not associated with the risk of islet autoimmunity (vitamin C: HR 0.91: 95% CI (0.80, 1.03), iron: 0.98 (0.87, 1.10)) or type 1 diabetes (vitamin C: 1.01 (0.87, 1.17), iron: 0.92 (0.78, 1.08)), neither was the use of vitamin C or iron supplements associated with the outcomes. In conclusion, no association was found between maternal vitamin C or iron intake during pregnancy and the risk of islet autoimmunity or type 1 diabetes in the offspring.  相似文献   
33.
34.
Valproate is effective in treating bipolar disorder characterized by rapid cycling or acute mania, although the mechanism of action is unclear. In contrast to other treatments for depression, 21 days of treatment in rats with valproate (100, 200 or 400 mg/kg) did not significantly alter the hypothermia induced by 8-hydroxy-2-(di-n-propyl)aminotetralin (8-OH-DPAT), an agonist at serotonin-1A receptors. Treatment with valproate also had no effect on radioligand binding to serotonin-1A, serotonin-2 or -adrenergic receptors. Based on these animal studies in frontal cortex and hippocampus, the therapeutic benefit of valproate in mood disorders does not appear to involve adaptive changes in serotonin-1A, serotonin-2 or -adrenergic receptor number.  相似文献   
35.
The European Network of Health Promoting School (ENHPS) program aims to foster healthy lifestyles for school populations by developing supportive teaching and learning environments conducive to promotion of health. Most European countries have joined the network since its organization in 1993. This paper describes how the European, national, and local aims of the ENHPS program have been realized in Finnish schools during the first year of the second triennium (1997-1999). Substantial development related to health promotion has occurred in the Finnish ENHPS schools. A safe school environment was emphasized, and networking with other schools was encouraged at the international and national levels. Attitudes toward the ENHPS program generally were positive. However, Finnish schools have emphasized developing "structures" for health promotion. In the future, efforts should concentrate on students' active participation in the activities of health promotion in everyday teaching and learning situations.  相似文献   
36.
This register study includes all patients under 18 years in Finland discharged from psychiatric inpatient treatment in 1990 (n = 818) and 1993 (n = 958). The prevalence of children and adolescents in the population who had previously been treated was about 7–8 per 10,000. The incidence of new cases of children and adolescents who had previously been inpatients within the last year was about 5–6 per 10,000 in this age group. The prevalence was lowest in the preschool group (about 1:10,000) and highest in the adolescent group (about 12–14:10,000). About two-thirds of inpatients were boys. Adjustment disorders (DSM-III-R) were the most common diagnosis both in 1990 and 1993 (about 30%). Mood and anxiety disorders were the second most frequent (19–23%) and disruptive behaviour disorders the third most frequent (13–15%) diagnostic category. The diagnostic profiles differed largely according to sex and age. Accepted: 18 May 1998  相似文献   
37.
FLFQPQRF-NH2 (F8Famide; morphine-modulating peptide), isolated from bovine brain, is an FMRFamide-like peptide with opioid analgesia modulating effects. In the rat brain, F8Famide is immunohistochemically localized in neurons of the medial hypothalamus and medulla oblongata. Neuropeptide Y (NPY) is structurally related to F8Famide and the mammalian FMRFamide-like immunoreactivity (LI) was once thought to be due to an NPY-like peptide. We compared the anatomical distribution of F8Famide-LI with the localization of enkephalin- and NPY-LI-containing structures in the rat brain to find out if NPY or enkephalins coexist with F8Famide-LI. Cryostat sections of colchicine-treated Wistar rat brains were incubated with specific antisera against F8Famide, NPY, YGGFMRGL (Met-enkephalin-Arg-Gly-Leu), or YGGFMRF (Met-enkephalin-Arg-Phe) raised in rabbits. The immunoreactivity was visualized by the peroxidase - antiperoxidase or immunofluorescence method. The light microscopic mirror method was applied to study the colocalization of F8Famide and NPY. The F8Famide-immunoreactivity was concentrated in smaller areas of medial hypothalamus and nucleus of the solitary tract than that of enkephalins and NPY. In all brain areas, the distributions of F8Famide-, enkephalin- and NPY-immunoreactive neurons were distinct. F8Famide-, NPY- and enkephalin-LI-containing nerve terminals were seen in the nucleus of the solitary tract and in the lateral parabrachial nucleus. These results show that the neuronal systems containing F8Famide-, enkephalin- or NPY-LI are anatomically separate in all brain regions. However, there are terminal areas in which more than one type of these immunoreactivities are detected. These results have anatomical correlation with pharmacological reports, suggesting modulatory functions for these peptides on regulation of blood pressure, feeding behaviour and endocrine functions.  相似文献   
38.
39.
A total of 44 181 serum samples from 16 733 pregnant women were analyzed for findings suggesting primary Toxoplasma infection. Thirty-seven newborns exposed to maternal primary Toxoplasma infection in utero were studied prospectively with ultrasound, CT, and MRI for signs of intrauterine infection. Their mothers had been treated during pregnancy, and all infants were treated. The children were assigned to three groups according to their mothers' serological status, and the radiological results were compared with the clinical outcome. Although radiological signs were scarce, ultrasound findings combined with maternal serology were found to be significantly related to clinical outcome. Received: 19 October 1994 Accepted: 28 April 1996  相似文献   
40.
The possible role of personality patterns and psychosocial factors in breast cancer has been studied extensively, through both human and animal experiments. The data are conflicting, and the conclusions controversial. This review will serve two purposes. First, we present evidence that behavioral patterns most commonly linked to breast cancer risk are at least partly regulated by estrogens. This section will suggest that some estrogen-regulated behaviors may be markers of increased breast cancer risk. Second, we will briefly review recent findings in animals connecting psychosocial factors to cancer. We also will address the plausible biological mechanisms. The literature suggests that estrogens, particularly when exposure occurs during the critical developmental periods, such as in utero, puberty, pregnancy, and menopause, influence affective behaviors and increase breast cancer risk. The affective behaviors include depression, aggression, and alcohol intake. Thus, psychosocial and personality factors do not necessarily have a direct impact on breast cancer risk; instead, estrogens have a dual effect on behavior and on the breast.  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