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   3580883篇
  免费   263728篇
  国内免费   8726篇
耳鼻咽喉   48909篇
儿科学   118605篇
妇产科学   99813篇
基础医学   503515篇
口腔科学   102171篇
临床医学   325167篇
内科学   697077篇
皮肤病学   82631篇
神经病学   293727篇
特种医学   139408篇
外国民族医学   1129篇
外科学   535958篇
综合类   79303篇
现状与发展   6篇
一般理论   1399篇
预防医学   278685篇
眼科学   81772篇
药学   265102篇
  10篇
中国医学   6969篇
肿瘤学   191981篇
  2018年   37607篇
  2017年   29138篇
  2016年   33506篇
  2015年   38109篇
  2014年   52423篇
  2013年   79477篇
  2012年   105698篇
  2011年   111678篇
  2010年   67174篇
  2009年   64379篇
  2008年   105107篇
  2007年   111414篇
  2006年   113276篇
  2005年   109093篇
  2004年   105931篇
  2003年   101996篇
  2002年   98869篇
  2001年   167389篇
  2000年   172023篇
  1999年   145571篇
  1998年   42009篇
  1997年   37547篇
  1996年   37573篇
  1995年   36488篇
  1994年   33780篇
  1993年   31730篇
  1992年   116018篇
  1991年   112589篇
  1990年   109329篇
  1989年   105900篇
  1988年   97659篇
  1987年   95944篇
  1986年   90739篇
  1985年   86986篇
  1984年   65120篇
  1983年   55662篇
  1982年   32968篇
  1981年   29629篇
  1979年   59677篇
  1978年   41849篇
  1977年   35548篇
  1976年   33153篇
  1975年   35348篇
  1974年   42335篇
  1973年   40372篇
  1972年   37727篇
  1971年   35254篇
  1970年   32472篇
  1969年   31060篇
  1968年   28386篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
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   
102.
103.
104.
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   
105.
106.
107.
108.
109.
Pre-eclamptic toxaemia (PET) may be associated with both endothelial dysfunction (ED) and sleep-disordered breathing (SDB). It was hypothesised that females with PET would demonstrate both SDB and ED, and that a correlation between these two would suggest a potential causative association. A total of 17 females with PET and 25 matched females with uncomplicated pregnancy were studied. They underwent a nocturnal ambulatory sleep study (using Watch_PAT100) and noninvasive evaluation of endothelial function utilising the reactive hyperaemia test (using Endo_PAT 2000). A higher ratio of post- to pre-occlusion pulse-wave amplitude (endothelial function index (EFI)) indicated better endothelial function. Females with PET had a significantly higher respiratory disturbance index (RDI) and lower EFI than controls (18.4+/-8.4 versus 8.3+/-1.3.h(-1), and 1.5+/-0.1 versus 1.8+/-0.1, respectively). Blood pressure significantly correlated with RDI and with EFI. EFI tended to correlate with RDI. In conclusion, these results suggest that both sleep-disordered breathing and endothelial dysfunction are more likely to occur in females with pre-eclamptic toxaemia than in females with uncomplicated pregnancies. The current authors speculate that respiratory disturbances contribute to the functional abnormality of the blood vessels seen in females with pre-eclamptic toxaemia, although causality cannot be determined based on this study.  相似文献   
110.
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