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   2591955篇
  免费   185422篇
  国内免费   7574篇
耳鼻咽喉   34295篇
儿科学   85341篇
妇产科学   71666篇
基础医学   364185篇
口腔科学   69691篇
临床医学   235174篇
内科学   516224篇
皮肤病学   62506篇
神经病学   213947篇
特种医学   100004篇
外国民族医学   736篇
外科学   386785篇
综合类   50445篇
现状与发展   5篇
一般理论   979篇
预防医学   196863篇
眼科学   56828篇
药学   188511篇
  8篇
中国医学   5336篇
肿瘤学   145422篇
  2021年   20111篇
  2019年   20763篇
  2018年   29412篇
  2017年   22686篇
  2016年   26342篇
  2015年   29625篇
  2014年   40589篇
  2013年   60675篇
  2012年   80568篇
  2011年   84854篇
  2010年   51197篇
  2009年   49302篇
  2008年   79304篇
  2007年   84140篇
  2006年   85884篇
  2005年   82023篇
  2004年   78983篇
  2003年   76299篇
  2002年   73573篇
  2001年   128474篇
  2000年   131400篇
  1999年   110566篇
  1998年   31291篇
  1997年   27953篇
  1996年   28236篇
  1995年   27407篇
  1994年   25088篇
  1993年   23450篇
  1992年   85175篇
  1991年   81578篇
  1990年   78798篇
  1989年   76075篇
  1988年   69478篇
  1987年   68004篇
  1986年   63554篇
  1985年   60524篇
  1984年   44949篇
  1983年   37955篇
  1982年   22461篇
  1981年   19995篇
  1979年   38968篇
  1978年   27447篇
  1977年   23257篇
  1976年   21504篇
  1975年   22817篇
  1974年   26791篇
  1973年   25372篇
  1972年   23751篇
  1971年   21958篇
  1970年   20184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