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:      
  示例: 沙坡头地区,人工植被区,变化  检索词用空格隔开表示必须包含全部检索词,用“,”隔开表示只需满足任一检索词即可!
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   1143篇
  免费   62篇
  国内免费   13篇
儿科学   77篇
妇产科学   4篇
基础医学   146篇
口腔科学   64篇
临床医学   123篇
内科学   203篇
皮肤病学   46篇
神经病学   36篇
特种医学   245篇
外科学   81篇
综合类   30篇
预防医学   56篇
眼科学   13篇
药学   31篇
  1篇
肿瘤学   62篇
  2024年   4篇
  2023年   4篇
  2022年   3篇
  2021年   7篇
  2020年   10篇
  2019年   8篇
  2018年   16篇
  2017年   7篇
  2016年   13篇
  2015年   28篇
  2014年   26篇
  2013年   42篇
  2012年   26篇
  2011年   25篇
  2010年   56篇
  2009年   52篇
  2008年   23篇
  2007年   36篇
  2006年   24篇
  2005年   28篇
  2004年   22篇
  2003年   28篇
  2002年   22篇
  2001年   15篇
  2000年   7篇
  1999年   29篇
  1998年   82篇
  1997年   77篇
  1996年   60篇
  1995年   53篇
  1994年   38篇
  1993年   45篇
  1992年   8篇
  1991年   23篇
  1990年   16篇
  1989年   43篇
  1988年   35篇
  1987年   27篇
  1986年   19篇
  1985年   19篇
  1984年   9篇
  1983年   12篇
  1982年   14篇
  1981年   14篇
  1980年   15篇
  1979年   4篇
  1978年   13篇
  1977年   11篇
  1976年   10篇
  1975年   8篇
排序方式: 共有1218条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
BACKGROUND: Acquired cerebriform intradermal naevus (CIN) is a rare form of pseudo cutis verticis gyrata. CASE REPORT: A case of acquired CIN of the scalp in a 46-year-old male patient is presented. The clinical and histopathological presentations of CIN are described and the therapeutic possibilities are discussed. CONCLUSIONS: In each individual case the physician must decide whether to do surgery or follow a wait-and-see policy. There is little risk of malignant change of CIN, and surgical excision of such lesions often involves evident mutilation.  相似文献   
6.
Objective: Right upper lobe collapse is a common radiographic finding in intubated children. We hypothesized that deep suctioning and uncontrolled negative pressures during endotracheal tube suctioning were significant contributory factors. Methods : The incidence of right upper lobe (RUL) collapse in intubated, ventilated children on a paediatric cardiac intensive care unit was determined over a 3-month period ( n = 102). Graduated suction catheters and suction vacuums of < 165 cm H2O were then introduced. Another prospective audit was carried out 3 months later ( n = 60). Results : We found that 24% developed RUL collapse and 4 developed an apical pneumothorax. Following the introduction of graduated catheters and controlled vacuums pressures, a significant reduction in the incidence of RUL collapse, to 7%, was observed ( p < 0.05). Conclusions : We conclude that high negative pressure and deep-suctioning causes RUL collapse in children. Any lobar collapse not only prolongs the child's stay in intensive care, but can be associated with further morbidity which may have a serious implication. By improving suctioning technique this morbidity can be significantly reduced.  相似文献   
7.
8.
标题 a)口服左旋-Sotatol治疗心肌梗死后左室功能不全患者生存研究(SWORD):试验依据、设计和方法   b)右旋-Sotatol对亚急性和陈旧性心肌梗死后左室功能不全患者病死率的影响研究作者 WaldoAL,CammAJ,deruyterH,等a)AmJCardiol,1995,75:1023~1027b)Lancet,1996,348:7~12  研究疾病:充血性心力衰竭。目的:右旋-Sotatol为一种具有专一性钾通道阻滞作用的抗心律失常药物。本研究将对其降低心肌梗死后左室功能不全…  相似文献   
9.
10.
Superoxide, an agent which attenuates the half-life of nitric oxide, is metabolized and synthesized by superoxide dismutase (SOD) and xanthine oxidase, respectively. Over the last few years much work has focused on the role of nitric oxide in human parturition. The aim of this study was to determine whether the onset of human parturition is associated with a change in the expression of copper/zinc superoxide dismutase (Cu/Zn SOD), manganese superoxide dismutase (Mn SOD) or xanthine oxidase within the uterus. Samples of myometrium, placenta, decidua and fetal membranes were obtained from women before and after the onset of labour at term. Immunocytochemistry was used to localize Cu/Zn SOD, Mn SOD and xanthine oxidase and measure SOD enzyme activity. Cu/Zn and Mn SOD-like immunoreactivity was detected in syncytiotrophoblast cells, villous stromal cells and endothelial cells of blood vessels in the placenta. In the myometrium Cu/Zn and Mn SOD were localized to myocytes and endothelial cells and to some vascular smooth muscle cells. In the fetal membranes we observed staining for Cu/Zn SOD and Mn SOD in the amnion, chorion, extravillous trophoblast and decidua. There was no difference in SOD enzyme activity or staining intensity for SOD between different cell types before and during labour. Xanthine oxidase immunoreactivity was identified in each of the tissues examined and again there was no difference in immunostaining in tissues obtained from women delivered before or after the onset of labour. These results show that the pregnant uterus is capable of both synthesizing and degrading superoxide and suggest that superoxide dismutase and xanthine oxidase may play a role in the maintenance of uterine quiescence during pregnancy, but not in the initiation of parturition.   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