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   2601519篇
  免费   186079篇
  国内免费   7587篇
耳鼻咽喉   34497篇
儿科学   85648篇
妇产科学   71911篇
基础医学   365451篇
口腔科学   69871篇
临床医学   236294篇
内科学   518150篇
皮肤病学   62724篇
神经病学   214742篇
特种医学   100258篇
外国民族医学   737篇
外科学   387923篇
综合类   50561篇
现状与发展   5篇
一般理论   982篇
预防医学   197965篇
眼科学   56968篇
药学   189067篇
  8篇
中国医学   5352篇
肿瘤学   146071篇
  2021年   20293篇
  2019年   20893篇
  2018年   29602篇
  2017年   22852篇
  2016年   26492篇
  2015年   29806篇
  2014年   40871篇
  2013年   61084篇
  2012年   81238篇
  2011年   85503篇
  2010年   51518篇
  2009年   49639篇
  2008年   79886篇
  2007年   84715篇
  2006年   86432篇
  2005年   82574篇
  2004年   79590篇
  2003年   76838篇
  2002年   74077篇
  2001年   128591篇
  2000年   131477篇
  1999年   110683篇
  1998年   31428篇
  1997年   28036篇
  1996年   28340篇
  1995年   27492篇
  1994年   25160篇
  1993年   23511篇
  1992年   85284篇
  1991年   81688篇
  1990年   78885篇
  1989年   76148篇
  1988年   69566篇
  1987年   68096篇
  1986年   63645篇
  1985年   60604篇
  1984年   45038篇
  1983年   38001篇
  1982年   22512篇
  1981年   20050篇
  1979年   39020篇
  1978年   27494篇
  1977年   23290篇
  1976年   21538篇
  1975年   22877篇
  1974年   26825篇
  1973年   25408篇
  1972年   23801篇
  1971年   21997篇
  1970年   20226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