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   5108093篇
  免费   390836篇
  国内免费   15525篇
耳鼻咽喉   71519篇
儿科学   164609篇
妇产科学   136777篇
基础医学   761042篇
口腔科学   144069篇
临床医学   467082篇
内科学   930753篇
皮肤病学   120890篇
神经病学   426199篇
特种医学   200432篇
外国民族医学   1144篇
外科学   764839篇
综合类   144661篇
现状与发展   24篇
一般理论   2896篇
预防医学   423223篇
眼科学   121135篇
药学   366194篇
  26篇
中国医学   13231篇
肿瘤学   253709篇
  2021年   56863篇
  2019年   59246篇
  2018年   76171篇
  2017年   58473篇
  2016年   64941篇
  2015年   77308篇
  2014年   111716篇
  2013年   177439篇
  2012年   143234篇
  2011年   151259篇
  2010年   131731篇
  2009年   131523篇
  2008年   137339篇
  2007年   147204篇
  2006年   154879篇
  2005年   148881篇
  2004年   150169篇
  2003年   139679篇
  2002年   128710篇
  2001年   201773篇
  2000年   199138篇
  1999年   178776篇
  1998年   76276篇
  1997年   70982篇
  1996年   69050篇
  1995年   64487篇
  1994年   58481篇
  1993年   54249篇
  1992年   133690篇
  1991年   128720篇
  1990年   124321篇
  1989年   121029篇
  1988年   111902篇
  1987年   109843篇
  1986年   104135篇
  1985年   101362篇
  1984年   81758篇
  1983年   72047篇
  1982年   53109篇
  1981年   49046篇
  1980年   45897篇
  1979年   72786篇
  1978年   56065篇
  1977年   49206篇
  1976年   45820篇
  1975年   46760篇
  1974年   52824篇
  1973年   50578篇
  1972年   47381篇
  1971年   44099篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
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   
993.
994.
995.
芦荟自古就被用作化妆品和药物添加剂,近来更受喜爱。虽应用广泛,但过敏反应罕有报道。作者用芦荟叶的油性提取物、来自整个植株的芦荟粉及浓缩的芦荟凝胶,对相继就诊的702例患者做斑贴试验。设计专门的问卷调查芦荟的使用、使用原因、使用部位、不良反应、患者职业、个人爱好及是否为遗传性过敏体质。患者均未对任一制剂发生任何反应。需对芦荟所含的两种成分加以鉴别:即芦荟叶皮含有的具有促进肠蠕动、潜在抗菌及抗癌特性的蒽醌类物质。  相似文献   
996.
997.
The absence of the temporary incisors could be to a genetic illness or to some multiple premature extractions. These extractions are the aftermaths of the carious lesions or some traumatisms underwent by the temporary incisors. Beyond measure the loss of the space, the premature loss some temporary incisors very often assign the relational development of the child and disturb its psychological development and the aesthetic function. Across some cases clinics, the authors show that the replacement of the temporary incisors is the therapeutic ideal solution. Indeed, the child prosthesis, replacing the temporary absent incisors, solves the psychological, aesthetic and relational problems of the child.  相似文献   
998.
The onset of the sporadic Creutzfeldt-Jakob disease is usually characterized by dementia or neurological symptoms. We are reporting the case of a 31 year-old man with a sporadic Creutzfeldt-Jakob disease characterized by a schizophrenia-like onset. The schizophrenic symptoms developed for sixteen months before the neurological symptoms appeared. The psychiatric onset of the present case was linked with the early age of onset and the long duration of the disease and could have been influenced by polymorphism of the codon 129 of the prion protein gene (PRNP) and a type of pathological prion protein (PrPres).  相似文献   
999.
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   
1000.
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