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   601篇
  免费   33篇
  国内免费   21篇
耳鼻咽喉   3篇
儿科学   40篇
妇产科学   1篇
基础医学   78篇
口腔科学   17篇
临床医学   69篇
内科学   111篇
皮肤病学   20篇
神经病学   52篇
特种医学   121篇
外科学   36篇
综合类   12篇
一般理论   1篇
预防医学   31篇
眼科学   2篇
药学   28篇
肿瘤学   33篇
  2023年   2篇
  2022年   5篇
  2021年   14篇
  2020年   4篇
  2019年   2篇
  2018年   3篇
  2017年   7篇
  2016年   10篇
  2015年   13篇
  2014年   17篇
  2013年   20篇
  2012年   12篇
  2011年   19篇
  2010年   34篇
  2009年   41篇
  2008年   15篇
  2007年   31篇
  2006年   19篇
  2005年   15篇
  2004年   16篇
  2003年   4篇
  2002年   8篇
  2001年   11篇
  2000年   5篇
  1999年   8篇
  1998年   35篇
  1997年   37篇
  1996年   30篇
  1995年   31篇
  1994年   11篇
  1993年   19篇
  1992年   3篇
  1991年   6篇
  1990年   11篇
  1989年   13篇
  1988年   19篇
  1987年   15篇
  1986年   9篇
  1985年   12篇
  1984年   6篇
  1983年   7篇
  1982年   12篇
  1981年   5篇
  1980年   9篇
  1978年   7篇
  1977年   6篇
  1976年   7篇
  1975年   5篇
  1957年   1篇
  1953年   1篇
排序方式: 共有655条查询结果,搜索用时 15 毫秒
41.
A controlled trial of elective intervention with continuous inflating pressure (CIP) was performed in infants with severe hyaline membrane disease who weighed more than 1000 g at birth. Infants entered the trial if their arterial oxygen tension (PaO2) fell below 60 mmHg while breathing a fractional inspired oxygen concentration (F1O2) greater than 0-95. 11 out of 12 infants in the CIP-treated group and 10 out of 12 in the control group survived. 7 treated and 6 control infants required mechanical ventilation. When CIP was started the Pao2 of the treated infants increased, and they breathed high concentrations of oxygen for a significantly shorter period than the control infants. During the 31-month duration of the trial 107 other infants with severe hyaline membrane disease were admitted who did not meet the criteria for entry to the trial. 37 survived after breathing high concentrations of oxygen (F1O2 greater than 0-60) spontaneously without any ventilatory assistance, and the remaining 70 infants were already being ventilated on their arrival in the unit, usually because they had required mechanical ventilation during transfer from other hospitals. The neonatal survival rate for those infants born in this hospital during the study period was 88% (50 out of 57 infants) and for those referred from other hospitals it was 69% (51 out of 74 infants). The maximum further increase in overall survival rate that might have been achieved in our population of infants if CIP had been initiated very early in the course of the illness was 5%--i.e. from 77% (101/131) to 82% (107/131).  相似文献   
42.
43.
44.
Color Doppler ultrasound (US) with point-spectral analysis was performed on eight patients with postbiopsy renal transplant arteriovenous fistulas. Waveform analysis of the supplying artery documented decreased resistive indices in all cases and increased flow velocities in seven. The peak-systolic flow velocity in the arteries supplying the fistulas ranged from 55 to 180 cm/sec (mean, 92 cm/sec), while the range in normal arteries was 20-52 cm/sec (mean, 32 cm/sec). The resistive indices of the arteries supplying the fistulas ranged from 0.31 to 0.50 (mean, 0.45), while the resistive indices of the normal arteries ranged from 0.60 to 0.92 (mean, 0.74). Arterialization of the venous waveform from the draining vein was also documented in all cases. In six cases, the increased flow velocities resulted in increased color saturation toward white in the supplying artery (n = 2) or in both the artery and the draining vein (n = 4), which was detectable on the realtime image. In six cases, flow turbulence resulted in localized tissue vibration, which appeared as random color assignment in extravascular renal parenchyma adjacent to the fistula. Knowledge of these imaging and Doppler characteristics should aid in the identification of renal transplant arteriovenous fistulas with color Doppler US.  相似文献   
45.

Background  

Recent evidence, both animal and human, suggests that modifiable factors during fetal and infant development predispose for cardiovascular disease in adult life and that they may become possible future targets for prevention. One of these factors is maternal psychosocial stress, but so far, few prospective studies have been able to investigate the longer-term effects of stress in detail, i.e. effects in childhood. Therefore, our general aim is to study whether prenatal maternal psychosocial stress is associated with an adverse cardio-metabolic risk profile in the child at age five.  相似文献   
46.
47.
A single photon emission computed tomographic method was designed for the measurement of radiopharmaceutical uptake in brain tumors. Results of phantom studies showed a correlation coefficient of .99 when measured volume was compared with actual volume. The correlation coefficient for measured radioactivity concentration compared with the actual concentration was .97. In 13 meningiomas the correlation between in vivo SPECT measurements of uptake and in vitro measurements in samples of the same tumors removed surgically was .84; when two tumors that contained regions of necrosis and fibrosis were excluded it was .93. This method can be used for in vivo quantitative assessment of pharmacokinetics of labeled drug uptake in human brain tumors.  相似文献   
48.
49.
50.
Canthaxanthin induces apoptosis in human cancer cell lines   总被引:3,自引:1,他引:2  
To investigate the possibility that canthaxanthin inhibits cancer cell growth by inducing apoptosis, human WiDr colon adenocarcinoma and SK- MEL-2 melanoma cells were treated with two different doses of the carotenoid for 48 h. Canthaxanthin was incorporated and/or associated to cells. The treatment with the carotenoid caused growth inhibition in both cell types. Concomitantly, apoptosis was induced. Increasing time of exposure and carotenoid concentration, this effect was more pronounced. At 48 h, the percentages of apoptotic cells were 13 and 15, using 1 microM canthaxanthin, and 18 and 20, using 10 microM canthaxanthin in WiDr and SK-MEL-2 cells, respectively. This study represents the first demonstration that canthaxanthin is able to induce apoptosis in tumour cells.   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