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   372篇
  免费   41篇
耳鼻咽喉   21篇
儿科学   6篇
妇产科学   8篇
基础医学   22篇
口腔科学   15篇
临床医学   13篇
内科学   67篇
皮肤病学   14篇
神经病学   5篇
特种医学   9篇
外科学   109篇
综合类   4篇
预防医学   13篇
眼科学   13篇
药学   21篇
肿瘤学   73篇
  2023年   2篇
  2022年   7篇
  2021年   20篇
  2020年   10篇
  2019年   22篇
  2018年   23篇
  2017年   9篇
  2016年   15篇
  2015年   18篇
  2014年   29篇
  2013年   22篇
  2012年   32篇
  2011年   35篇
  2010年   12篇
  2009年   17篇
  2008年   18篇
  2007年   18篇
  2006年   28篇
  2005年   18篇
  2004年   24篇
  2003年   11篇
  2002年   16篇
  2000年   1篇
  1997年   1篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
排序方式: 共有413条查询结果,搜索用时 15 毫秒
1.
Molecular characterization of Wuchereria bancrofti is essential to develop suitable anti-filarial drugs and vaccines. We describe here isolation, sequence analysis and cloning of a partial cDNA of an enzyme superoxide dismutase from this parasite. The immunoscreening of a lambda zap W. bancrofti microfilarial (Mf) cDNA library with microfilaremic sera had resulted in the isolation of several seroreactive clones including, WbSOD. This clone contained a 309 bp insert and showed significant nucleotide and deduced amino acid sequence homologies to the superoxide dismutases of other nematode parasites. The antioxidant property of this enzyme may have important contribution in the defense mechanism of the parasite against host immune response.  相似文献   
2.
3.
4.
BackgroundLeisure-time physical inactivity has a high prevalence and associated disease burden. Adult inactivity research ignores earlier life factors from which later life influences can originate. We aimed to establish whether early life factors influence adult inactivity.MethodsThe 1958 British Birth Cohort is a nationwide follow-up study of all births during 1 week in March, 1958. The outcome of the present study was leisure-time inactivity, defined as activity frequency of less than once a week, assessed at ages 33 years, 42 years, and 50 years (n=12 776). Early life factors (birth to 16 years) were categorised into three domains (physical, social, behavioural). We assessed stability of inactivity from 33 years to 50 years and associations with adult inactivity using logistic regression of: factors within domains, the three domains combined (ie, multivariable associations), and allowing for adult factors. Missing values were imputed with multiple imputation chained equations.FindingsAt each adult age, about 32% of participants were inactive (31% at 33 years, 34% at 42 years, and 30% at 50 years). 1189 (9%) were inactive at all three ages. In analysis of the three domains simultaneously, factors related to adult inactivity were: short prepubertal stature, poor hand control or physical coordination, and poor cognition (physical); low class at birth, minimal parental education, poor household amenities, parental divorce, and institutional care (social); and inactivity, average or lower sports aptitude, smoking, and externalising and unsociable behaviours (behavioural). Odds ratios for inactivity at age 33 years ranged from 0·86 per SD increase in cognition (95% CI 0·82–0·91) to 1·41 (1·23–1·61) for average or lower sports aptitude. Associations weakened slightly but were mostly maintained after adjustment for adult covariates. After allowing for adult covariates participants with unskilled manual backgrounds had 23% higher odds of inactivity at 50 years than those from professional or managerial backgrounds.InterpretationOur study, based on self-report, focuses only on leisure-time inactivity. However, to have repeat, prospective data on inactivity spanning several decades in adulthood is rare, and leisure-time inactivity is likely to be amenable to modification. Adult inactivity is only moderately stable, providing opportunities for behaviour change. Factors from early life are associated with adult inactivity, allowing for early identification of groups vulnerable to later inactivity.FundingThis work was supported by the Department of Health Policy Research Programme through the Public Health Research Consortium. The Great Ormond Street and University College London Institute of Child Health was supported in part by the Department of Health's National Institute for Health Biomedical Research Centre.  相似文献   
5.
6.
7.
8.
Objectives To identify independent predictors of outcome in patients with adenoid cystic carcinoma (ACC) of the paranasal sinuses and skull base.Design Meta-analysis of the literature and data from the International ACC Study Group.Setting University-affiliated medical center.Participants The study group consisted of 520 patients, 99 of them from the international cohort. The median follow-up period was 60 months (range, 32 to 100 months).Main Outcome Measures Overall survival (OS) and disease-specific survival (DSS).Results The 5-year OS and DSS of the entire cohort were 62% and 67%, respectively. The local recurrence rate was 36.6%, and the regional recurrence rate was 7%. Distant metastasis, most commonly present in the lung, was recorded in 106 patients (29.1%). In the international cohort, positive margins and ACC of the sphenoid or ethmoidal sinuses were significant predictors of outcome (p < 0.001). Perineural invasion and adjuvant treatment (radiotherapy or chemoradiation) were not associated with prognosis.Conclusion Tumor margin status and tumor site are associated with prognosis in ACC of the paranasal sinuses, whereas perineural invasion is not. Adjuvant treatment apparently has no impact on outcome.  相似文献   
9.
10.
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