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   1256篇
  免费   76篇
  国内免费   11篇
耳鼻咽喉   6篇
儿科学   90篇
妇产科学   10篇
基础医学   109篇
口腔科学   26篇
临床医学   141篇
内科学   280篇
皮肤病学   20篇
神经病学   41篇
特种医学   318篇
外科学   133篇
综合类   14篇
一般理论   1篇
预防医学   39篇
眼科学   6篇
药学   41篇
肿瘤学   68篇
  2023年   3篇
  2022年   2篇
  2021年   13篇
  2020年   7篇
  2019年   13篇
  2018年   17篇
  2017年   6篇
  2016年   11篇
  2015年   21篇
  2014年   19篇
  2013年   34篇
  2012年   23篇
  2011年   34篇
  2010年   35篇
  2009年   28篇
  2008年   31篇
  2007年   57篇
  2006年   38篇
  2005年   35篇
  2004年   31篇
  2003年   16篇
  2002年   17篇
  2001年   18篇
  2000年   12篇
  1999年   24篇
  1998年   96篇
  1997年   70篇
  1996年   76篇
  1995年   52篇
  1994年   54篇
  1993年   61篇
  1992年   12篇
  1991年   12篇
  1990年   13篇
  1989年   40篇
  1988年   25篇
  1987年   40篇
  1986年   24篇
  1985年   29篇
  1984年   24篇
  1983年   17篇
  1982年   22篇
  1981年   23篇
  1980年   28篇
  1979年   6篇
  1978年   16篇
  1977年   18篇
  1976年   20篇
  1975年   13篇
  1970年   2篇
排序方式: 共有1343条查询结果,搜索用时 15 毫秒
191.
The Mark IV system for radionuclide computed tomography of the brain   总被引:5,自引:0,他引:5  
  相似文献   
192.
193.
194.
To determine the relation between basic clinical characteristics and resource utilisation in paediatric intensive care, an open prospective study was performed. Resource utilisation was expressed using the therapeutic intervention score system (TISS) and length of stay (LOS), from which total resource utilisation per admission (TISSTOT) and average daily resource utilisation (TISSMEAN = TISSTOT/LOS) were obtained. Overall 593 admissions, totalling 3130 days, were included. Mortality was 8.4% and non-survivors accounted for 14.1% of overall resource utilisation. In non-survivors, TISSTOT and TISSMEAN were higher, whereas LOS was not different from survivors'. Severity of illness, surgical status, significant chronic comorbidity, emergency admission, and transfer status constituted the major predictive determinants of TISSTOT (r2 = 0.19) and TISSMEAN (r2 = 0.45) in multiple regression analysis. High resource utilisation in high risk patients was probably warranted, as effectiveness of prolonged intensive treatment was demonstrated. It is concluded that TISSTOT and TISSMEAN are appropriate, non-monetary measures of resource utilisation, a considerable proportion of which are determined by a concise set of basic clinical characteristics.  相似文献   
195.
The staging of rectosigmoid villous adenomas is difficult when based only on clinical or endoscopic findings, even when superficial biopsies are taken. Echoendoscopy (EE) with a 7.5 and 12 MHz transducer heads provides good visualization of these lesions. The role of EE in the staging of villous adenomas presenting as benign lesions was prospectively studied. Among 47 patients who had an echoendoscopic investigation for villous adenoma during a 18 month period, 25 had lesions believed to be benign based on clinical and endoscopic findings. In 23 patients (group I, superficial biopsies showed no malignancy; in 2 patients (group II), with 3 lesions, biopsies were positive for in situ carcinoma. Comparisons were made between echographic images and operative specimens. A complete EE investigation was possible in all cases. In group I, there was one tumor T3N+ that was diagnosed by EE only. Twelve other patients had neoplastic lesions limited to the mucosa or submucosa only, and 10 had benign lesions. The integrity of the muscularis propria was imaged in all cases but EE did not differentiate benign lesions from neoplastic lesions invading the mucosa. In group II, parietal staging was correct in 2 of 3 cases. In addition to clinical examination and endoscopic investigations, EE seems useful in the staging of large or high located villous adenomas as well as for the best therapeutic choice.  相似文献   
196.
197.
铁皮石斛试管苗快速繁殖的研究   总被引:28,自引:0,他引:28  
兰科植物铁皮石斛(Dendrobium candidum Wall.ex Lind1.)的茎为常用名贵中药。多年来,主要依靠采收野生品种供药用和出口,致使野生资源枯竭,现已成为日益稀少的濒危植物。兰属种子和石斛属种子试管繁殖已积累不少资料,但是有关铁皮石斛种子试管繁殖的研究只有少量简单的报道,对其种子在试管繁殖过程中,所需外界条件的研究也不够  相似文献   
198.
Dunn  EK; Macchia  RJ; Solomon  NA 《Radiology》1981,139(1):175-180
The testicular scintigraphic findings of nine patients with surgically and pathologically proved torsion of the testis of over 24 hours duration are reviewed. In the delayed blood-pool images each showed the classical avascular twisted testicle with a variable peripheral rim of hyperemia. In the dynamic blood-flow phase, eight revealed a perceptible increase of vascular perfusion in the scrotal region on the affected side, in addition to the testicular radionuclide angiogram peculiarities previously described for missed testicular torsion. This pattern of perfusion was seen only in torsion of over one day duration. A low salvage probability is expected in these cases.  相似文献   
199.
200.
Pancreatic transplant imaging   总被引:1,自引:0,他引:1  
Forty-four clinical episodes of suspected (pancreas) transplant rejection in 17 pancreatic transplantation patients were reviewed retrospectively. The clinical impression of acute graft rejection, chronic rejection, or nonrejection in each episode was correlated with the results of 19 nuclear medicine, 12 ultrasound (US), and 44 magnetic resonance (MR) imaging studies. US was found to be a moderately sensitive (82%) method of detecting graft rejection. US also was effective in identifying intra- and peripancreatic fluid accumulations. Nuclear medicine imaging was also a sensitive technique (86%) and the only modality that provided physiologic information regarding graft perfusion. MR imaging allowed correct prediction of the presence or absence of graft rejection in 39 of 44 cases (sensitivity, 100%; specificity, 76%) and was an effective means of detecting pathologic fluid collections. Nuclear medicine, US, and MR imaging are all believed to be sensitive methods of detecting graft rejection and are complementary adjuncts to the clinical evaluation of pancreatic transplants.  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