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   2587826篇
  免费   185077篇
  国内免费   7570篇
耳鼻咽喉   34274篇
儿科学   85203篇
妇产科学   71574篇
基础医学   363682篇
口腔科学   69667篇
临床医学   234533篇
内科学   515641篇
皮肤病学   62454篇
神经病学   213468篇
特种医学   99897篇
外国民族医学   736篇
外科学   386474篇
综合类   50395篇
现状与发展   5篇
一般理论   968篇
预防医学   196183篇
眼科学   56676篇
药学   188020篇
  8篇
中国医学   5333篇
肿瘤学   145282篇
  2021年   19994篇
  2019年   20627篇
  2018年   29294篇
  2017年   22594篇
  2016年   26227篇
  2015年   29507篇
  2014年   40447篇
  2013年   60434篇
  2012年   80241篇
  2011年   84502篇
  2010年   51012篇
  2009年   49154篇
  2008年   79039篇
  2007年   83852篇
  2006年   85585篇
  2005年   81746篇
  2004年   78753篇
  2003年   76072篇
  2002年   73357篇
  2001年   128425篇
  2000年   131341篇
  1999年   110514篇
  1998年   31255篇
  1997年   27923篇
  1996年   28223篇
  1995年   27387篇
  1994年   25073篇
  1993年   23429篇
  1992年   85173篇
  1991年   81581篇
  1990年   78802篇
  1989年   76070篇
  1988年   69476篇
  1987年   68010篇
  1986年   63552篇
  1985年   60517篇
  1984年   44949篇
  1983年   37947篇
  1982年   22458篇
  1981年   19986篇
  1979年   38961篇
  1978年   27443篇
  1977年   23253篇
  1976年   21497篇
  1975年   22814篇
  1974年   26791篇
  1973年   25371篇
  1972年   23750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
111.
112.
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   
113.
114.
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   
115.
116.
Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.  相似文献   
117.
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   
118.
119.
120.
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