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   3752篇
  免费   321篇
  国内免费   149篇
耳鼻咽喉   14篇
儿科学   123篇
妇产科学   50篇
基础医学   495篇
口腔科学   40篇
临床医学   430篇
内科学   844篇
皮肤病学   77篇
神经病学   339篇
特种医学   397篇
外科学   288篇
综合类   68篇
预防医学   382篇
眼科学   92篇
药学   266篇
  2篇
中国医学   1篇
肿瘤学   314篇
  2021年   26篇
  2019年   52篇
  2018年   56篇
  2017年   33篇
  2016年   40篇
  2015年   61篇
  2014年   44篇
  2013年   124篇
  2012年   142篇
  2011年   152篇
  2010年   119篇
  2009年   114篇
  2008年   141篇
  2007年   244篇
  2006年   133篇
  2005年   151篇
  2004年   109篇
  2003年   106篇
  2002年   116篇
  2001年   121篇
  2000年   100篇
  1999年   111篇
  1998年   115篇
  1997年   107篇
  1996年   100篇
  1995年   81篇
  1994年   60篇
  1993年   75篇
  1992年   69篇
  1991年   83篇
  1990年   99篇
  1989年   116篇
  1988年   91篇
  1987年   74篇
  1986年   81篇
  1985年   79篇
  1984年   64篇
  1983年   55篇
  1982年   37篇
  1981年   40篇
  1980年   42篇
  1979年   51篇
  1978年   32篇
  1977年   41篇
  1976年   55篇
  1975年   43篇
  1974年   27篇
  1973年   23篇
  1972年   24篇
  1971年   26篇
排序方式: 共有4222条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
The authors extracted 11 case files of patients undergoing radical prostatectomy following MRI studies from a series of 192 MRI examinations of the prostate with histological confirmation of the diagnosis. This series is part of a prospective study in which MRI was always interpreted prior to histological results. The diagnosis of prostatic cancer was confirmed in 9 cases on the basis of a hyposignal on T2-weighted scans. In 4 cases, extracapsular spread of the tumour was demonstrated by MRI and was confirmed at surgery. In the cases in which the cancer was visible on MRI, the diagnosis of local spread proved to be accurate. The debate concerning the role of MRI in prostatic disease is not definitively resolved, but this preliminary series indicates the potential and the limitations of this technique.  相似文献   
5.
Twenty patients with advanced malignant disease submitted to autologous bone marrow transplantation with marrow either unpurged (10 patients) or purged in vitro with mafosfamide (10 patients) after ablative chemotherapy, received simultaneously autologous peripheral blood stem cells (PBSC) collected during one to three 3 h cytapheresis procedures. The kinetics of the hematological recovery of these patients were compared to those of a group of patients suffering from similar diseases and grafted in the same institution with either unpurged marrow only (14 patients) or purged in vitro with mafosfamide (six patients). The median times to reach 10(9)/l leukocytes, 0.5 x 10(9)/l polymorphs, and 50 x 10(9)/l platelets were reduced by 10, 10, and 13 days, respectively, in patients transfused with both autologous bone marrow and peripheral blood stem cells as compared to those receiving bone marrow only. A reduction in the numbers of days spent in hospital post-transplantation (p less than 0.01), of days of fever greater than 38 degrees C (p = NS), and of platelet (p = 0.07) and of red blood cell transfusions (p less than 0.01) were also observed in the group of patients grafted with bone marrow and PBSC.  相似文献   
6.
Granulomatous prostatitis is an uncommon disease that can prostatic carcinoma on both digital rectal examination and transrectal ultrasound. Four patients who underwent magnetic resonance imaging of the prostate had a histological diagnosis of graanulomatous prostatitis; three of them had recent urinary tract infections. The other patient had an associated midline prostatic cyst and a focus of malignancy. T1-and T2-weighted spin-echo images were obtained in all cases. Peripheral zone lesions of decreased signal intensity, suggestive of carcinoma,were found in all four patients on T2-weighted images. Granulomatous prostatitis should be considered in the differential diagnosis of low signal intensity areas with prostatic magnetic resonance imaging. Correspondence to; P.A. Gevenois  相似文献   
7.
8.
The latissimus dorsi musculocutaneous flap was used to provide chest wall coverage in 40 patients following mastectomy to treat recurrent cancer in irradiated breasts. Although the axillary region had received 50 to 55 grays, the neurovascular pedicle was never jeopardized, thus assuring vascularisation of the flap. In two cases, a small area of skin necrosis in the upper inner border of the flap was observed. Complete healing occurred within weeks. The authors advocate this fast and simple surgical procedure when the quality of the skin and/or the extent of resection prevents primary closure.  相似文献   
9.
2-Nitro-oxaphenalenes are synthetic chemicals which were synthesized in the authors' laboratory. They are the most efficient mutagenic compounds on mammalian cells in culture. They are chemically related to the nitro-naphthofuran family by the displacement of the heterocycle on the naphthalene ring. Since nitro-naphthofurans have a strong mutagenic activity in bacterial tests without metabolic activation and are active in-vivo carcinogens, the purpose of this study was to demonstrate the carcinogenic activity of two 2-nitro-oxaphenalenes. The two compounds were injected s.c. into Wistar rats initially 6-weeks-old. They were dissolved in dimethylsulfoxide (DMSO) at a concentration of 1 mg/ml. A s.c. injection of 0.5 ml containing 0.5 mg of carcinogen was given once a week in the neck of each animal tested. Five control animals were not injected and five animals received 0.5-ml injection of DMSO every week to serve as a control. The animals developed tumors only at the site of injection. The tumors were classified as high grade fibrosarcomas. This experiment demonstrates that: (i) 2-nitro-oxaphenalenes are very active in-vivo carcinogens in rats; (ii) there is a good correlation between the high mutagenic activity especially in mammalian tests and the strong carcinogenicity of the compounds; and (iii) the presence of a 6-methoxy group increases by two-fold the carcinogenic potential.  相似文献   
10.
Propofol, administered intravenously for induction and as a continuous maintenance anaesthetic with nitrous oxide, was compared, in a group of elderly patients scheduled for ophthalmic surgery, with an anaesthetic technique (etomidate, alfentanil, nitrous oxide and isoflurane) specifically chosen to be haemodynamically stable and evanescent in action. Both techniques resulted in similar effects on blood pressure after induction, intubation and surgical incision, but propofol did not prevent increases in heart rate as effectively at these times. Furthermore, during maintenance anaesthesia, cardiovascular stability and anaesthetic depth were more easily achieved in the group where etomidate, alfentanil and isoflurane were used. Propofol decreased intra-ocular pressure after intubation, while in both groups recovery was rapid with no significant complications. A subgroup of patients receiving alpha-methyldopa had significantly longer post-anaesthetic recovery times.  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