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   283篇
  免费   23篇
  国内免费   1篇
儿科学   15篇
妇产科学   5篇
基础医学   25篇
口腔科学   5篇
临床医学   54篇
内科学   85篇
皮肤病学   4篇
神经病学   14篇
特种医学   23篇
外科学   23篇
综合类   6篇
预防医学   27篇
眼科学   1篇
药学   8篇
肿瘤学   12篇
  2021年   2篇
  2018年   3篇
  2017年   2篇
  2016年   4篇
  2015年   7篇
  2013年   3篇
  2012年   3篇
  2011年   5篇
  2010年   6篇
  2009年   13篇
  2008年   15篇
  2007年   7篇
  2006年   13篇
  2005年   8篇
  2004年   4篇
  2003年   5篇
  2002年   2篇
  2000年   8篇
  1999年   11篇
  1998年   11篇
  1997年   9篇
  1996年   13篇
  1995年   8篇
  1994年   16篇
  1993年   10篇
  1991年   2篇
  1989年   5篇
  1988年   11篇
  1987年   6篇
  1986年   5篇
  1985年   10篇
  1984年   5篇
  1983年   8篇
  1982年   6篇
  1981年   7篇
  1980年   5篇
  1977年   2篇
  1976年   6篇
  1975年   2篇
  1973年   2篇
  1972年   2篇
  1971年   5篇
  1969年   2篇
  1965年   3篇
  1963年   4篇
  1962年   2篇
  1956年   2篇
  1939年   1篇
  1938年   1篇
  1927年   1篇
排序方式: 共有307条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
1. The action of etomidate (0.125-4.0 mg/kg) injected intravenously or into the right atrium (time of injection about 1 sec) was investigated in cats under different central nervous conditions. 2. In decerebrate unanaesthetized animals and in lightly anaesthetized (pentobarbitone) animals with an intact CNS etomidate (0.25-4 mg/kg i.v.) caused a decrease of the spontaneous lumbar fusimotor activity and a strong depression of the fusimotor pinnareflex. Partly a reversal of this reflex from excitation to inhibition was observed. The effects occurred within 20 sec after the injection and lasted for 5-70 min, showing a clear non-linear relationship with the injected dose. 3. In encephale isole preparations etomidate (0.125-1 mg/kg injected intra-right atrially) caused distinct changes of the spontaneous EEB (decrease of frequency, increase of amplitude, occurrence of steeper waves) and a depression of the arousal reactions in the EEB following different stimuli (acoustic stimuli and different stimuli in the area of the face and eyes). These effects occurred within 8 sec after the injection and lasted up to 40 min, dependent upon the injected dose. 4. The character and the principal similarity of the results observed in decerebrate animals and in animals with intact CNS suggest that a considerable part of the action of etomidate consists of a depression of the activity and reactivity of the brain stem reticular formation.  相似文献   
46.
Proximal femoral focal deficiency (PFFD)   总被引:1,自引:0,他引:1  
Levinson  ED; Ozonoff  MB; Royen  PM 《Radiology》1977,125(1):197
  相似文献   
47.
48.
49.
Failure-free survival, defined as the absence of relapse, non-relapse mortality or addition of another systemic therapy, has been proposed as a potential endpoint for clinical trials, but its use has only been reported for single-center studies. We measured failure-free survival in a prospective observational cohort of patients (n=575) with both newly diagnosed and existing chronic graft-versus-host disease from nine centers. Failure was observed in 389 (68%) patients during the observation period. The median follow up of all patients was 30.9 months, and the median failure-free survival was 9.8 months (63% at 6 months, 45% at 1 year, and 29% at 2 years). Of the variables measured at enrollment, ten were associated with shorter failure-free survival: higher National Institutes of Health 0–3 skin score, higher National Institutes of Health 0–3 gastrointestinal score, worse range of motion summary score, lower forced vital capacity (%), bronchiolitis obliterans syndrome, worse quality of life, moderate to severe hepatic dysfunction, absence of treatment for gastric acid, female donor for male recipient, and prior grade II–IV acute graft-versus-host disease. Addition of a new systemic treatment, the major cause of failure, was associated with an increased risk of subsequent non-relapse mortality (hazard ratio=2.06, 95% confidence interval: 1.29–3.32; P<0.003) and decreased survival (hazard ratio=1.51, 95% confidence interval: 1.04–2.18; P<0.03). These results show that fewer than half of patients on systemic treatment will be failure-free survivors at 1 year, and fewer than a third will reach 2 years without experiencing failure. Better treatments are needed for chronic graft-versus-host disease. Clinicaltrials.gov identifier: NCT00637689.  相似文献   
50.
Data from many laboratory and clinical investigations indicate that CD34+ cells comprise approximately 1% of human bone marrow (BM) mononuclear cells, including the progenitor cells of all the lymphohematopoietic lineages and lymphohematopoietic stem cells (stem cells). Because stem cells are an important but rare cell type in the CD34+ cell population, investigators have subdivided the CD34+ cell population to further enrich stem cells. The CD34+/CD38- cell subset comprises less than 10% of human CD34+ adult BM cells (equivalent to < 0.1% of marrow mononuclear cells), lacks lineage (lin) antigens, contains cells with in vitro replating capacity, and is predicted to be highly enriched for stem cells. The present investigation tested whether the CD34+/CD38- subset of adult human marrow generates human hematopoiesis after transfer to preimmune fetal sheep. CD34+/ CD38- cells purified from marrow using immunomagnetic microspheres or fluorescence-activated cell sorting generated easily detectable, long- term, multilineage human hematopoiesis in the human-fetal sheep in vivo model. In contrast, transfer of CD34+/CD38+ cells to preimmune fetal sheep generated only short-term human hematopoiesis, possibly suggesting that the CD34+/CD38+ cell population contains relatively early multipotent hematopoletic progenitor cells, but not stem cells. This work extends the prior in vitro evidence that the earliest cells in fetal and adult human marrow lack CD38 expression. In summary, the CD34+/ CD38- cell population has a high capacity for long-term multilineage hematopoietic engraftment, suggesting the presence of stem cells in this minor adult human marrow cell subset.  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