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   2591400篇
  免费   185364篇
  国内免费   7573篇
耳鼻咽喉   34281篇
儿科学   85314篇
妇产科学   71647篇
基础医学   364021篇
口腔科学   69721篇
临床医学   235123篇
内科学   516165篇
皮肤病学   62499篇
神经病学   213833篇
特种医学   100067篇
外国民族医学   736篇
外科学   387092篇
综合类   50520篇
现状与发展   5篇
一般理论   971篇
预防医学   196645篇
眼科学   56695篇
药学   188204篇
  8篇
中国医学   5336篇
肿瘤学   145454篇
  2021年   20029篇
  2019年   20688篇
  2018年   29365篇
  2017年   22652篇
  2016年   26300篇
  2015年   29560篇
  2014年   40516篇
  2013年   60609篇
  2012年   80436篇
  2011年   84727篇
  2010年   51136篇
  2009年   49236篇
  2008年   79198篇
  2007年   84043篇
  2006年   85769篇
  2005年   81898篇
  2004年   78893篇
  2003年   76228篇
  2002年   73496篇
  2001年   128498篇
  2000年   131423篇
  1999年   110584篇
  1998年   31310篇
  1997年   27968篇
  1996年   28266篇
  1995年   27413篇
  1994年   25102篇
  1993年   23462篇
  1992年   85231篇
  1991年   81645篇
  1990年   78865篇
  1989年   76127篇
  1988年   69529篇
  1987年   68057篇
  1986年   63604篇
  1985年   60565篇
  1984年   44993篇
  1983年   37991篇
  1982年   22484篇
  1981年   20017篇
  1979年   39003篇
  1978年   27484篇
  1977年   23279篇
  1976年   21511篇
  1975年   22831篇
  1974年   26817篇
  1973年   25392篇
  1972年   23768篇
  1971年   21979篇
  1970年   20207篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
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   
93.
94.
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   
95.
96.
97.
98.
99.
A Survey of Plants Used as Wild Vegetables in Four Districts of Botswana   总被引:1,自引:0,他引:1  
A survey of plants used as wild vegetables was conducted in four districts of Botswana in August and September 2005. The objective was to determine which wild plants were used as vegetables in the study area, and to document their cooking and preservation methods. Fourteen species representing seven families were mentioned as wild vegetables. In addition, six species from four families had other uses in traditional medicine. The implications of the documented processing methods on the retention of nutrients in the vegetables are discussed.  相似文献   
100.
In chronic myeloid leukaemia, CD34(+) stem/progenitor cells appear resistant to imatinib mesylate (IM) in vitro and in vivo. To investigate the underlying mechanism(s) of IM resistance, it is essential to quantify Bcr-Abl kinase status at the stem cell level. We developed a flow cytometry method to measure CrkL phosphorylation (P-CrkL) in samples with <10(4) cells. The method was first validated in wild-type (K562) and mutant (BAF3) BCR-ABL(+) as well as BCR-ABL(-) (HL60) cell lines. In response to increasing IM concentration, there was a linear reduction in P-CrkL, which was Bcr-Abl specific and correlated with known resistance. The results were comparable to those from Western blotting. The method also proved to be reproducible with small samples of normal and Ph(+) CD34(+) cells and was able to discriminate between Ph(-), sensitive and resistant Ph(+) cells. This assay should now enable investigators to unravel the mechanism(s) of IM resistance in stem cells.  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