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   2227084篇
  免费   155531篇
  国内免费   4041篇
耳鼻咽喉   32854篇
儿科学   70882篇
妇产科学   62288篇
基础医学   315501篇
口腔科学   66053篇
临床医学   195040篇
内科学   424488篇
皮肤病学   51228篇
神经病学   177002篇
特种医学   87690篇
外国民族医学   595篇
外科学   339314篇
综合类   48939篇
现状与发展   7篇
一般理论   712篇
预防医学   158141篇
眼科学   53272篇
药学   171549篇
  9篇
中国医学   5172篇
肿瘤学   125920篇
  2018年   22765篇
  2017年   18252篇
  2016年   20710篇
  2015年   22555篇
  2014年   30800篇
  2013年   46808篇
  2012年   62346篇
  2011年   66435篇
  2010年   39035篇
  2009年   36307篇
  2008年   62875篇
  2007年   67963篇
  2006年   68463篇
  2005年   65858篇
  2004年   63526篇
  2003年   61370篇
  2002年   59897篇
  2001年   106754篇
  2000年   110131篇
  1999年   91972篇
  1998年   24789篇
  1997年   22237篇
  1996年   21623篇
  1995年   20275篇
  1994年   18824篇
  1993年   17722篇
  1992年   69861篇
  1991年   67445篇
  1990年   66283篇
  1989年   64334篇
  1988年   59309篇
  1987年   58169篇
  1986年   55420篇
  1985年   52695篇
  1984年   39260篇
  1983年   33338篇
  1982年   19629篇
  1979年   36930篇
  1978年   26009篇
  1977年   22844篇
  1976年   20526篇
  1975年   23254篇
  1974年   27434篇
  1973年   26726篇
  1972年   25394篇
  1971年   23804篇
  1970年   22325篇
  1969年   21462篇
  1968年   19816篇
  1967年   17775篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The aim of the study was to determine the effect of β-glucan on the cytotoxicity and genotoxicity of polypectomized patient's fecal water (FW). Polypectomized volunteers (n = 69) were randomly assigned to consume bread with or without β-glucan, for 3 months. FW was collected at the beginning (t = 0), the 30th and 90th day and 2 wk after the intervention. Cytotoxicity and genotoxicity were estimated on Caco-2 cells, using trypan blue exclusion test and comet assay, respectively. Gastrointestinal symptoms were recorded and subjects kept a 3-day food diary at baseline and after completion. Trypan blue exclusion test revealed cell survival of approximately 87% after incubation with FW. The FW samples showed 49% genotoxicity at the baseline. Genotoxicity in the intervention group decreased during the trial reaching statistical significance on the 90th day compared to control. An increase was noticed 2 wk after the trial, but it still remained significantly lower compared to control. Group-specific analysis for β-glucan also revealed significant decrease in the genotoxicity on the 90th day compared to baseline. β-glucan ingestion in polypectomized patients significantly decreased the genotoxicity of their FW. Our findings suggest that β-glucan consumption could possibly provide protection against colon cancer development.  相似文献   
82.
INTRODUCTIONPsoriasis is a chronic inflammatory condition that affects the skin and joints, and is associated with cardiovascular risk factors, including metabolic syndrome (MetS). We aimed to assess the prevalence of MetS in patients with psoriasis and determine whether there was a correlation between psoriasis severity and MetS in a Singapore population.METHODSThis was a cross-sectional study of patients with psoriasis, aged 18–69 years, who attended a tertiary dermatology referral centre in Singapore from October 2007 to February 2009. Fasting glucose, lipids, blood pressure, Psoriasis Area and Severity Index, and body mass index were measured. MetS was diagnosed in the presence of three or more criteria of the modified National Cholesterol Education Program Adult Treatment Panel III.RESULTSAmong 338 patients with psoriasis, there were 238 (70.4%) men and 100 (29.6%) women, who were Chinese (n = 228; 67.5%), Malay (n = 52; 15.4%) and Indian (n = 58; 17.2%). The prevalence of MetS was 45.1%. MetS was 44% more prevalent in patients older than 50 years (p = 0.02). Malay patients with psoriasis were significantly more likely to have hypertriglyceridaemia, elevated fasting plasma glucose and abdominal obesity. There was no significant correlation between psoriasis severity and risk of MetS.CONCLUSIONThe prevalence of MetS in patients with psoriasis in Singapore was 45.1%, or nearly threefold higher than the Singapore general population. Patients with psoriasis should be screened yearly for MetS and any modifiable cardiovascular risk factors should be actively controlled.  相似文献   
83.
84.
85.
86.
87.
88.
89.
Porocarcinoma is an unusual, locally aggressive and potentially fatal neoplasm. Several cutaneous malignancies have been described in association with porocarcinoma, including squamous cell carcinoma, basal cell carcinoma and tricholemmal carcinoma. Previous reports have indicated that the occurrence of malignant tumours in combination with porocarcinoma is extremely rare, in particular with regard to Bowen disease (BD). We report an uncommon case of porocarcinoma occurring synchronously in a single BD lesion in a 63‐year‐old woman with multiple BD lesions. The clinical and histological findings confirmed this diagnosis.  相似文献   
90.
Children who expect they can bring about good outcomes and avoid bad outcomes tend to experience more personal successes. Little is known about factors that contribute to these ‘control expectancies’. The purpose of the present study was to determine whether children's internal control expectancies occur in the context of parents’ internal control expectancies, low family strain, and high family cohesiveness and whether these factors are more strongly related to daughters’ than sons’ control expectancies. A community sample of 85 children aged 9–11 years and their parents (85 mothers; 63 fathers) completed rating scales. Fathers’ more internal control expectancies and mothers’ reports of fewer family strains were associated with daughters’ but not sons’ greater internal control expectancies, and greater family cohesiveness was related to both daughters’ and sons’ internal control orientations. These findings suggest that family factors may contribute to children's, particularly daughters’, development of internal control expectancies.  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