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   346篇
  免费   17篇
  国内免费   19篇
耳鼻咽喉   1篇
儿科学   16篇
妇产科学   2篇
基础医学   27篇
口腔科学   14篇
临床医学   45篇
内科学   56篇
皮肤病学   7篇
神经病学   17篇
特种医学   44篇
外科学   37篇
综合类   26篇
预防医学   25篇
药学   47篇
中国医学   1篇
肿瘤学   17篇
  2023年   2篇
  2021年   5篇
  2020年   2篇
  2019年   5篇
  2018年   6篇
  2017年   3篇
  2016年   10篇
  2015年   9篇
  2014年   15篇
  2013年   18篇
  2012年   8篇
  2011年   8篇
  2010年   12篇
  2009年   16篇
  2008年   11篇
  2007年   18篇
  2006年   22篇
  2005年   12篇
  2004年   12篇
  2003年   13篇
  2002年   6篇
  2001年   8篇
  2000年   7篇
  1999年   7篇
  1998年   19篇
  1997年   15篇
  1996年   10篇
  1995年   6篇
  1994年   12篇
  1993年   10篇
  1991年   4篇
  1989年   6篇
  1988年   2篇
  1987年   4篇
  1986年   2篇
  1985年   6篇
  1984年   5篇
  1983年   10篇
  1982年   3篇
  1981年   3篇
  1980年   4篇
  1979年   3篇
  1978年   2篇
  1977年   7篇
  1976年   2篇
  1970年   1篇
  1967年   1篇
  1966年   2篇
  1963年   1篇
  1962年   1篇
排序方式: 共有382条查询结果,搜索用时 0 毫秒
11.
12.
13.

Background  

The objective of this study was to demonstrate the use of an association rule mining approach to discover associations between selected socioeconomic variables and the four most leading causes of cancer mortality in the United States. An association rule mining algorithm was applied to extract associations between the 1988–1992 cancer mortality rates for colorectal, lung, breast, and prostate cancers defined at the Health Service Area level and selected socioeconomic variables from the 1990 United States census. Geographic information system technology was used to integrate these data which were defined at different spatial resolutions, and to visualize and analyze the results from the association rule mining process.  相似文献   
14.
Transgenic mice with both alleles of the p53 tumor suppressor gene product 'knocked out' by gene targeting are susceptible to early development of tumors, chiefly lymphomas and sarcomas. Compared with the control group, administration of dehydroepiandrosterone (DHEA) at 0.3% of the diet to male p53-deficient mice extended their lifespan by delaying death due to neoplasms (from 105 to 166 days on study, P = 0.002), primarily by suppressing lymphoblastic lymphoma (from 45 to 6% of neoplastic deaths, P = 0.010). Treatment with a synthetic DHEA analog, 16alpha-fluoro-5-androsten-17-one (compound 8354), at 0.15% of the diet also increased lifespan, to 140 days for mice that developed tumors (P = 0.037). The effects of these steroids on lifespan and tumor development did not appear to be strongly related to inhibition of food consumption and weight gain, in that a group pair-fed with control diet to the reduced food consumption of the DHEA-treated group developed and died of the same types of neoplasms at the same rate as the controls fed ad libitum. The chemopreventive effect of these steroids has been proposed to be due to suppression of DNA synthesis by inhibition of glucose 6-phosphate dehydrogenase, the rate-limiting enzyme of the pentose phosphate pathway. Although DHEA and its analog are strong non- competitive inhibitors of this enzyme in vitro, treatment with DHEA did not deplete cellular nucleotide pools in the liver, as would have been predicted. The chemopreventive effect of DHEA in this model may be due to steroid-induced thymic atrophy and suppression of T cell lymphoma, permitting these mice to survive long enough to develop tumors with longer latency.   相似文献   
15.
Objective : To establish the prevalence of specific chronic conditions of childhood in the Auckland area and to quantify resource use by these children.
Methodology : Estimates were made from available registry data and published data sources of the population of children with selected chronic conditions resident in the Auckland Area Health Board area. Resource use data were extracted for admissions to Auckland public hospitals and from providers of community based technology services.
Results : The largest community prevalence groups are those with asthma, intellectual handicap, congenital heart disease and epilepsy. Children aged 0-14 with chronic conditions accounted for at least 14340 hospital days stay in Auckland in 1992 at an estimated minimum cost of $7.9 million. Over 200 children are dependent on technological aids at home.
Conclusions : There are sparse data on the numbers and needs of children with chronic conditions in the population. A non-categorical approach which crosses disease entities may be the best method of meeting common needs.  相似文献   
16.
17.
The present paper explores the language of aging used, often unthinkingly, by nurses and policy makers. Terms so often used when describing aging, such as "frailty" and "dependence", are used in a way that implies a common knowledge, a point of convergence. It will be argued, using data gathered from research, that these terms often are a point of departure and that they may not signify a common understanding at all. From a postmodern perspective, it will be argued that it is at this point that common knowledge comes up against corporeal or embodied knowledge. In conclusion, the author will argue for a clinical encounter in which intersubjective meanings can be elucidated.  相似文献   
18.
Aim: The aim of this study was to determine if asthmatic children have viruses more commonly detected in lower airways during asymptomatic periods than normal children. Methods: Fifty‐five asymptomatic children attending elective surgical procedures (14 with stable asthma, 41 normal controls) underwent non‐bronchoscopic bronchoalveolar lavage. Differential cell count and PCR for 13 common viruses were performed. Results: Nineteen (35%) children were positive for at least one virus, with adenovirus being most common. No differences in the proportion of viruses detected were seen between asthmatic and normal ‘control’ children. Viruses other than adenovirus were associated with higher neutrophil counts, suggesting that they caused an inflammatory response in both asthmatics and controls (median BAL neutrophil count, 6.9% for virus detected vs. 1.5% for virus not detected, p = 0.03). Conclusions: Over one‐third of asymptomatic children have a detectable virus (most commonly adenovirus) in the lower airway; however, this was not more common in asthmatics. Viruses other than adenovirus were associated with elevated neutrophils suggesting that viral infection can be present during relatively asymptomatic periods in asthmatic children.  相似文献   
19.
20.
K-Ⅱ系k阿片激动剂U-50488的同类物。通过部分离体和整体实验比较了K-Ⅱ与U-50488的药理作用。实验发现,K-Ⅱ抑制电刺激兔输精管收缩的IC50值为0.42 nmol/L,U-50488为26.5 nmol/L;K-Ⅱ抑制小鼠运动功能(横筛法)的ED50值为1.7 mg/g,U-50488为15.3 mg/kg;K-Ⅱ的小鼠LD50值为152.5 mg/kg,U-50488为118.4 mg/g;K-Ⅱ明显降低小鼠自发活动的作用比U-50488强5倍。结果表明,K-Ⅱ是一个药理作用较U-50488强的k受体激动剂。  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