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   2589490篇
  免费   185265篇
  国内免费   7571篇
耳鼻咽喉   34281篇
儿科学   85262篇
妇产科学   71650篇
基础医学   363796篇
口腔科学   69683篇
临床医学   234921篇
内科学   515856篇
皮肤病学   62480篇
神经病学   213599篇
特种医学   99974篇
外国民族医学   736篇
外科学   386722篇
综合类   50428篇
现状与发展   5篇
一般理论   981篇
预防医学   196445篇
眼科学   56726篇
药学   188146篇
  8篇
中国医学   5331篇
肿瘤学   145296篇
  2021年   20033篇
  2019年   20671篇
  2018年   29326篇
  2017年   22627篇
  2016年   26261篇
  2015年   29538篇
  2014年   40487篇
  2013年   60501篇
  2012年   80318篇
  2011年   84615篇
  2010年   51065篇
  2009年   49201篇
  2008年   79132篇
  2007年   83940篇
  2006年   85675篇
  2005年   81871篇
  2004年   78816篇
  2003年   76141篇
  2002年   73407篇
  2001年   128462篇
  2000年   131378篇
  1999年   110542篇
  1998年   31270篇
  1997年   27942篇
  1996年   28230篇
  1995年   27400篇
  1994年   25089篇
  1993年   23440篇
  1992年   85202篇
  1991年   81608篇
  1990年   78826篇
  1989年   76102篇
  1988年   69511篇
  1987年   68034篇
  1986年   63562篇
  1985年   60541篇
  1984年   44957篇
  1983年   37962篇
  1982年   22466篇
  1981年   19996篇
  1979年   38978篇
  1978年   27458篇
  1977年   23268篇
  1976年   21507篇
  1975年   22827篇
  1974年   26803篇
  1973年   25390篇
  1972年   23766篇
  1971年   21962篇
  1970年   20196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