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   477篇
  免费   37篇
  国内免费   5篇
耳鼻咽喉   5篇
儿科学   49篇
妇产科学   3篇
基础医学   29篇
口腔科学   15篇
临床医学   62篇
内科学   94篇
皮肤病学   1篇
神经病学   6篇
特种医学   140篇
外科学   22篇
综合类   30篇
预防医学   23篇
眼科学   2篇
药学   17篇
肿瘤学   21篇
  2022年   2篇
  2021年   4篇
  2020年   1篇
  2019年   3篇
  2018年   9篇
  2017年   6篇
  2016年   9篇
  2015年   11篇
  2014年   18篇
  2013年   21篇
  2012年   11篇
  2011年   3篇
  2010年   11篇
  2009年   8篇
  2008年   9篇
  2007年   9篇
  2006年   8篇
  2005年   5篇
  2004年   9篇
  2003年   7篇
  2002年   7篇
  2001年   8篇
  2000年   6篇
  1999年   16篇
  1998年   30篇
  1997年   33篇
  1996年   34篇
  1995年   30篇
  1994年   30篇
  1993年   19篇
  1992年   4篇
  1991年   5篇
  1990年   6篇
  1989年   13篇
  1988年   17篇
  1987年   15篇
  1986年   16篇
  1985年   15篇
  1984年   8篇
  1983年   11篇
  1982年   4篇
  1981年   9篇
  1980年   5篇
  1979年   2篇
  1978年   2篇
  1977年   3篇
  1976年   5篇
  1975年   2篇
排序方式: 共有519条查询结果,搜索用时 15 毫秒
41.
A microcapillary method utilizing phthalate esters or an ultracentrifuge method are both capable of separating autologous from homologous erythrocytes in polytransfused patients. The microcapillary technique which is readily adaptable to blood bank laboratories provides a previously unavailable method for defining blood group antigen typings in transfused patients. Such typings are of vital importance in the laboratory evaluation of transfused patients with multiple or weak blood group antibodies.  相似文献   
42.
Total radical trapping antioxidant potential (TRAP) and exercise   总被引:1,自引:0,他引:1  
The relationship between physical activity, physical fitness and total radical trapping antioxidant potential (TRAP) was examined in the Northern Ireland Health and Activity Survey. This was a cross-sectional population study (n = 1600) using a two-stage probability sample of the population. TRAP was calculated using the sum of the individual serum antioxidant concentrations (urate, protein thiols, ascorbate, alpha tocopherol and bilirubin) multiplied by their respective stoichiometric values. Physical fitness was determined by estimation of VO2max by extrapolation from submaximal oxygen uptake, and physical activity was recorded by computer-assisted interview. Mean serum TRAP concentrations were significantly higher in males (653 +/- 8.2 mumol/l, mean +/- SEM) compared to females (564 +/- 8.0 mumol/l) (p < 0.0001). Both male and female smokers had significantly lower TRAP values than non-smokers (males p < 0.0001, females p = 0.02). In females, there was a positive relationship of TRAP with age (p < 0.001) and body mass index (p < 0.001) but a negative relationship with physical fitness (p < 0.05). The known beneficial effects of exercise and activity do not appear to be directly mediated through increased antioxidant status.   相似文献   
43.
PURPOSE: We compared hexaminolevulinate (Hexvix) fluorescence cystoscopy with white light cystoscopy for detecting carcinoma in situ. MATERIALS AND METHODS: In this multicenter study 298 patients with known or suspected bladder cancer underwent bladder instillation with 50 ml 8 mM hexaminolevulinate for 1 hour. Cystoscopy was then performed, first using standard white light and then hexaminolevulinate fluorescence cystoscopy. Lesions or suspicious areas identified under the 2 illumination conditions were mapped and biopsied for histological examination. In addition, 1 directed biopsy was obtained from an area appearing to be normal. RESULTS: Of 196 evaluable patients 29.6% (58 of 196) had carcinoma in situ, including 18 with carcinoma in situ alone, and 35 with carcinoma in situ and concomitant papillary disease, which was only detected on random biopsy in 5. Of the 18 patients with no concomitant papillary disease carcinoma in situ was detected only by hexaminolevulinate fluorescence in 4 and only by white light in 4. In the group with concomitant papillary disease carcinoma in situ was found only by hexaminolevulinate fluorescence in 5 patients and only by white light in 3. The proportion of patients in whom 1 or more carcinoma in situ lesions were found only by hexaminolevulinate cystoscopy was greater than the hypothesized 5% (p=0.0022). Overall more carcinoma in situ lesions were found by hexaminolevulinate than by white light cystoscopy in 22 of 58 patients (41.5%), while the converse occurred in 8 of 58 (15.1%). Biopsy results confirmed cystoscopy findings. Of a total of 113 carcinoma in situ lesions in 58 patients 104 (92%) were detected by hexaminolevulinate cystoscopy and 77 (68%) were detected by white light cystoscopy, while 5 were detected only on directed visually normal mucosal biopsy. Hexaminolevulinate instillation was well tolerated with no local or systemic side effects. CONCLUSIONS: In patients with bladder cancer hexaminolevulinate fluorescence cystoscopy with blue light can diagnose carcinoma in situ that may be missed with white light cystoscopy. Hexaminolevulinate fluorescence cystoscopy can be used in conjunction with white light cystoscopy to aid in the diagnosis of this form of bladder cancer.  相似文献   
44.
45.
Erythromycin treatment for gastrointestinal dysmotility in preterm infants   总被引:3,自引:0,他引:3  
To report our clinical experience on the use of oral erythromycin for the treatment of severe gastrointestinal dysmotility in preterm infants.

Methodology:


A case series study of seven preterm infants (six were very low birthweight) with severe intestinal dysmotility in a tertiary neonatal centre.

Results:


All responded favourably without adverse effects and tolerated full enteral feeding within 1–2 weeks of the commencement of the drug.

Conclusions:


As prolonged total parenteral nutrition carries significant risk of complications, this therapy could be considered in selected preterm infants who fail to establish enteral feeding after an extended period, and in whom an anatomically obstructive lesion of the gastrointestinal tract has been excluded. Meanwhile, we would caution against the widespread implementation of this therapeutic approach until formal evaluation by randomized controlled trials have established the exact role of erythromycin, or its analogues, in the treatment of intestinal dysmotility in preterm infants.  相似文献   
46.
BACKGROUND: Vascular lesions have become more evident in human immunodeficiency virus type 1 (HIV)-infected patients as the result of earlier diagnosis, improved treatment, and longer survival. Aortic root dilation in HIV-infected children has not previously been described. This study was undertaken to determine the prevalence of aortic root dilation in HIV-infected children and to evaluate some of the potential pathogenic mechanisms. METHODS: Aortic root measurements were incorporated into the routine echocardiographic surveillance of 280 children of HIV-infected women: an older cohort of 86 HIV-infected children and a neonatal cohort of 50 HIV-infected and 144 HIV-uninfected children. RESULTS: By repeated-measures analyses, mean aortic root measurements were significantly increased in HIV-infected children versus HIV-uninfected children (P values of < or =.04 and < or =.005 at 2 and 5 years of age, respectively, for aortic annulus diameter, sinuses of Valsalva, and sinotubular junction). Heart rate, systolic blood pressure, stroke volume, hemoglobin, and hematocrit were not significantly associated with aortic root size. Left ventricular dilation, increased serum HIV RNA levels, and lower CD4 cell count measurements were associated with aortic root dilation at baseline. CONCLUSIONS: Mild and nonprogressive aortic root dilation was seen in children with vertically transmitted HIV infection from 2 to 9 years of age. Aortic root size was not significantly associated with markers for stress-modulated growth; however, aortic root dilation was associated with left ventricular dilation, increased viral load, and lower CD4 cell count in HIV-infected children. As prolonged survival of HIV-infected patients becomes more prevalent, some patients may require long-term follow-up of aortic root size.  相似文献   
47.
48.
49.
收集脊柱损伤的信息对于脊髓损伤患者的诊断和治疗非常重要,设立脊髓损伤患者脊柱损伤基础数据集是为了规范脊柱损伤相关信息的收集方式和报告内容,学习并使用国际脊髓损伤脊柱损伤基础数据集,有助于规范和统一我国脊髓损伤患者脊柱损伤信息的收集,为相关治疗提供依据。本文将介绍国际脊髓损伤脊柱损伤基础数据集的研发过程,数据元素的内容以及数据编码的应用实例。  相似文献   
50.
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