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   936篇
  免费   42篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   42篇
妇产科学   9篇
基础医学   90篇
口腔科学   18篇
临床医学   54篇
内科学   301篇
皮肤病学   17篇
神经病学   33篇
特种医学   25篇
外科学   147篇
综合类   17篇
预防医学   41篇
眼科学   19篇
药学   42篇
中国医学   1篇
肿瘤学   119篇
  2023年   9篇
  2022年   9篇
  2021年   54篇
  2020年   33篇
  2019年   23篇
  2018年   45篇
  2017年   30篇
  2016年   28篇
  2015年   30篇
  2014年   51篇
  2013年   46篇
  2012年   91篇
  2011年   79篇
  2010年   39篇
  2009年   22篇
  2008年   45篇
  2007年   53篇
  2006年   41篇
  2005年   31篇
  2004年   34篇
  2003年   26篇
  2002年   20篇
  2001年   16篇
  2000年   15篇
  1999年   6篇
  1998年   8篇
  1997年   6篇
  1996年   4篇
  1995年   4篇
  1994年   4篇
  1992年   2篇
  1991年   6篇
  1990年   8篇
  1989年   5篇
  1988年   4篇
  1987年   2篇
  1986年   5篇
  1985年   2篇
  1983年   2篇
  1981年   2篇
  1979年   5篇
  1976年   3篇
  1975年   2篇
  1974年   5篇
  1973年   2篇
  1972年   4篇
  1971年   2篇
  1970年   3篇
  1968年   2篇
  1964年   2篇
排序方式: 共有980条查询结果,搜索用时 296 毫秒
51.

Background  

Half of the population of Africa will soon live in towns and cities where it can be protected from malaria by controlling aquatic stages of mosquitoes. Rigorous but affordable and scaleable methods for mapping and managing mosquito habitats are required to enable effective larval control in urban Africa.  相似文献   
52.
53.
54.
55.
56.
A Mexican family with partial congenital nephrogenic diabetes insipidus (NDI) that resulted from a mutation in the aquaporin-2 water channel (AQP2) was characterized, and the source of this rare mutation was traced to the family's town of origin in Mexico. Affected individuals with profound polyuria and polydipsia were homozygous for an autosomal recessive missense V168M mutation in the AQP2 gene. Expression in oocytes revealed that, although retained in the endoplasmic reticulum (ER) to a great extent, a considerable amount of the partially functional AQP2-V168M was expressed at the plasma membrane, and that its ER retention was less than AQP2-T126M, a functional mutant in severe recessive NDI. None of the affected AQP2-V168M individuals had neurologic deficits, which also suggested a milder form of the disease. The homozygous individuals reported subjective improvement in polyuria and polydipsia with the use of dDAVP (1-desamino-8-D-arginine-vasopressin). When clinically tested, infusion of dDAVP at variable doses produced a partial increase in the urinary osmolality in homozygous individuals and decreased their water intake. Heterozygotes were unaffected when compared with controls. Samples were obtained from the population of the Mexican town of origin of the family; 30% of the population was heterozygous for the V168M AQP2 mutation and 1% was homozygous for the mutation. The high frequency of this rare mutation in the town provides evidence for an important health care problem in the village with consequences for future generations.  相似文献   
57.
The microstructure, chemical composition and wettability of thermally and chemically modified Ti-6Al-4V alloy disks were characterized and correlated with the degree of radiolabeled fibronectin-alloy surface adsorption and subsequent adhesion of osteoblast-like cells. Heating either in pure oxygen or atmosphere (atm) resulted in an enrichment of Al and V within the surface oxide. Heating (oxygen/atm) and peroxide treatment both followed by butanol treatment resulted in a reduction in content of V, but not in Al. Heating (oxygen/atm) or peroxide treatment resulted in a thicker oxide layer and a more hydrophilic surface when compared with passivated controls. Post-treatment with butanol, however, resulted in less hydrophilic surfaces than heating or peroxide treatment alone. The greatest increases in the adsorption of radiolabeled fibronectin following treatment were observed with peroxide/butanol-treated samples followed by peroxide/butanol and heat/butanol, although binding was only increased by 20-40% compared to untreated controls. These experiments with radiolabeled fibronectin indicate that enhanced adsorption of the glycoprotein was more highly correlated with changes in chemical composition, reflected in a reduction in V content and decrease in the V/Al ratio, than with changes in wettability. Despite promoting only a modest elevation in fibronectin adsorption, the treatment of disks with heat or heat/butanol induced a several-fold increase in the attachment of MG63 cells promoted by a nonadhesive concentration of fibronectin that was used to coat the pretreated disks compared to uncoated disks. Therefore, results obtained with these modifications of surface properties indicate that an increase in the absolute content of Al and/or V (heat), and/or in the Al/V ratio (with little change in hydrophilicity; heat+butanol) is correlated with an increase in the fibronectin-promoted adhesion of an osteoblast-like cell line. It would also appear that the thermal treatment-induced enhancement of cell adhesion in the presence of this integrin-binding protein is due to its increased biological activity, rather than a mass effect alone, that appear to be associated with changes in chemical composition of the metallic surface. Future studies will investigate the influence of the surface chemical composition of various implantable alloys on protein adsorption and receptor-mediated cell adhesion. In addition, by altering the properties of bound osteogenic protein enhancing exposure to cell integrin binding domains, it may be possible to develop implant surfaces which enhance the attachment, adhesion and developmental response of osteoblast precursors leading to accelerated osseointegration.  相似文献   
58.
OBJECTIVE: To evaluate the efficacy of an interactive intervention in reducing distress related to radiation therapy (RT) among pediatric cancer participants as measured by occurrence of sedation, observed behavioral distress (OBD), and heart rate (HR). METHODS: Seventy-nine children receiving RT simulation were assigned randomly to a STARBRIGHT Hospital Pals group (i.e., interactive intervention group; IG) or modified control group (MCG). The interactive intervention included filmed modeling, exposure to an interactive Barney character, and passive auditory distraction. RESULTS: Children in the IG experienced significantly lower HR when compared with MCG participants. No differences were found in terms of sedation or OBD. CONCLUSIONS: The interactive intervention was effective at reducing RT-related distress (as measured by HR) and would be a useful tool in pediatric radiation oncology settings.  相似文献   
59.
60.
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