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   2588940篇
  免费   185189篇
  国内免费   7573篇
耳鼻咽喉   34280篇
儿科学   85224篇
妇产科学   71603篇
基础医学   363787篇
口腔科学   69675篇
临床医学   234739篇
内科学   515859篇
皮肤病学   62464篇
神经病学   213730篇
特种医学   99943篇
外国民族医学   736篇
外科学   386554篇
综合类   50402篇
现状与发展   5篇
一般理论   969篇
预防医学   196342篇
眼科学   56712篇
药学   188053篇
  8篇
中国医学   5331篇
肿瘤学   145286篇
  2021年   20004篇
  2019年   20650篇
  2018年   29326篇
  2017年   22616篇
  2016年   26261篇
  2015年   29524篇
  2014年   40480篇
  2013年   60506篇
  2012年   80322篇
  2011年   84564篇
  2010年   51046篇
  2009年   49187篇
  2008年   79110篇
  2007年   83925篇
  2006年   85658篇
  2005年   81808篇
  2004年   78794篇
  2003年   76116篇
  2002年   73389篇
  2001年   128457篇
  2000年   131385篇
  1999年   110536篇
  1998年   31267篇
  1997年   27936篇
  1996年   28232篇
  1995年   27399篇
  1994年   25076篇
  1993年   23431篇
  1992年   85187篇
  1991年   81588篇
  1990年   78810篇
  1989年   76081篇
  1988年   69502篇
  1987年   68021篇
  1986年   63567篇
  1985年   60526篇
  1984年   44956篇
  1983年   37958篇
  1982年   22467篇
  1981年   19989篇
  1979年   38973篇
  1978年   27445篇
  1977年   23257篇
  1976年   21498篇
  1975年   22823篇
  1974年   26790篇
  1973年   25378篇
  1972年   23754篇
  1971年   21964篇
  1970年   20187篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Primary chemotherapy administered to breast cancer patientsis the best model to identify baseline features able to predictwhich patients may be most likely to benefit or not from a cytotoxicregimen. In the March issue of Annals of Oncology two papersevaluated the predictive role of immunohistochemical p53 expressionon  相似文献   
72.
73.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  相似文献   
74.
75.
Bifid mandibular canal.   总被引:1,自引:0,他引:1  
PURPOSE: To determine the incidence and characteristics of bifid mandibular canals. METHODS: A retrospective study was performed using panoramic radiographs of 2012 patients subjected to dental treatment in the Dental Clinic of the Valencia University Dental School (Valencia, Spain) between 1996 and 1999. The goal was to investigate the presence of double mandibular canals. RESULTS: The extraoral panoramic radiographs revealed a total of 7 images suggestive of bifid canals. Mandibular computed tomography revealed the existence of this anatomic variant in 2 of 3 patients. An analysis was performed on the incidence of this type of image in extraoral panoramic radiography, its possible interpretations, and the clinical implications of bifid mandibular canals. CONCLUSIONS: In this study, 0.35% of canals were bifid. All cases were in women.  相似文献   
76.
77.
78.
79.
80.
The aim of this study was to determine whether patients with sickle cell disease (SCD) in steady state had pulmonary abnormalities seen on high-resolution computed tomography (HRCT) and whether any abnormalities correlated with contemporaneously diagnosed lung function abnormalities. A subsidiary question was whether the results of a noninvasive measure of haemolysis (end-tidal carbon monoxide (ETCO) levels) correlated with pulmonary function abnormalities. Thirty three patients with SCD, median (range) age 36 yrs (17-67 yrs) were examined. The degree of lobar volume loss and ground-glass opacification and prominence of central vessels on HRCT were quantitatively assessed. Pulmonary function was assessed by measurements of lung volumes, spirometry, gas transfer and oxygen saturation. ETCO levels were measured using an end-tidal CO monitor. Forced expiratory volume in one second (FEV1), forced vital capacity and total lung capacity significantly correlated with HRCT findings, particularly lobar volume loss. ETCO levels significantly negatively correlated with FEV1, vital capacity measured using a plethysmograph, specific airway conductance and arterial oxygen saturation measured by pulse oxymetry. In conclusion, the present results suggest that high-resolution computed tomography noninvasive assessment of haemolysis might be useful to identify sickle cell disease patients with respiratory function impairment.  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