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   1426044篇
  免费   96331篇
  国内免费   2904篇
耳鼻咽喉   20399篇
儿科学   43434篇
妇产科学   40018篇
基础医学   198817篇
口腔科学   40322篇
临床医学   118233篇
内科学   280573篇
皮肤病学   30629篇
神经病学   115542篇
特种医学   57613篇
外国民族医学   435篇
外科学   223832篇
综合类   31868篇
现状与发展   6篇
一般理论   436篇
预防医学   100376篇
眼科学   32265篇
药学   105156篇
  4篇
中国医学   2991篇
肿瘤学   82330篇
  2018年   22545篇
  2017年   18350篇
  2016年   20811篇
  2015年   12246篇
  2014年   16972篇
  2013年   25507篇
  2012年   35914篇
  2011年   44350篇
  2010年   28328篇
  2009年   25778篇
  2008年   43395篇
  2007年   48769篇
  2006年   37470篇
  2005年   38069篇
  2004年   37481篇
  2003年   37568篇
  2002年   35860篇
  2001年   63894篇
  2000年   65780篇
  1999年   55568篇
  1998年   14825篇
  1997年   13684篇
  1996年   13082篇
  1995年   12370篇
  1994年   11629篇
  1992年   42884篇
  1991年   41403篇
  1990年   40683篇
  1989年   39648篇
  1988年   37051篇
  1987年   36509篇
  1986年   34992篇
  1985年   33204篇
  1984年   24881篇
  1983年   21111篇
  1982年   12740篇
  1981年   11578篇
  1979年   23994篇
  1978年   17122篇
  1977年   14846篇
  1976年   13445篇
  1975年   15273篇
  1974年   18107篇
  1973年   17570篇
  1972年   16810篇
  1971年   15717篇
  1970年   14945篇
  1969年   14381篇
  1968年   13482篇
  1967年   12015篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
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   
43.
44.
45.
46.
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   
47.
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   
48.
In the 6th Basic Plan for Long-Term Electricity Supply and Demand (6th BPE) for Korea, for the first time, the environmental costs of air pollution caused by oxides of sulfur (SOx), oxides of nitrogen (NOx), and particulate matters (PM) from power plants were estimated and included. However, several deficiencies in evaluating the environmental costs were found. In this study, (1) the validity of the environmental costs used in the 6th BPE was assessed, (2) a systematic approach was suggested and used to improve the environmental costs estimation, and (3) the sensitivity of the cost of generating electricity to the environmental costs by fuel type with the proposed approach was discussed. We found that the applied environmental costs used in the 6th BPE did not fully include the demographic characteristics of Korea. By applying more realistic parameter values, it was found that the newly estimated environmental cost was about 23 times higher than the cost estimated in the original 6th BPE for coal-fired power plants and about 1.5 times higher for liquefied natural gas (LNG)-fired power plants, suggesting that LNG-fired power plants are more economical if using more realistic environmental costs. Thus, it is critical to check the validity of parameter values when calculating environmental costs.  相似文献   
49.
50.
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