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   3522913篇
  免费   285811篇
  国内免费   13494篇
耳鼻咽喉   47994篇
儿科学   111304篇
妇产科学   90805篇
基础医学   558060篇
口腔科学   95113篇
临床医学   322331篇
内科学   622919篇
皮肤病学   92367篇
神经病学   301131篇
特种医学   136673篇
外国民族医学   294篇
外科学   535352篇
综合类   103820篇
现状与发展   24篇
一般理论   2486篇
预防医学   303275篇
眼科学   80184篇
药学   241575篇
  27篇
中国医学   9469篇
肿瘤学   167015篇
  2021年   55461篇
  2020年   35350篇
  2019年   58445篇
  2018年   72030篇
  2017年   54919篇
  2016年   60435篇
  2015年   74518篇
  2014年   108857篇
  2013年   174399篇
  2012年   99983篇
  2011年   101449篇
  2010年   119031篇
  2009年   122825篇
  2008年   88372篇
  2007年   92592篇
  2006年   102007篇
  2005年   98100篇
  2004年   99233篇
  2003年   89900篇
  2002年   79516篇
  2001年   103525篇
  2000年   96215篇
  1999年   96198篇
  1998年   65039篇
  1997年   62925篇
  1996年   61071篇
  1995年   56457篇
  1994年   50695篇
  1993年   47332篇
  1992年   68182篇
  1991年   65471篇
  1990年   62148篇
  1989年   61228篇
  1988年   57002篇
  1987年   55793篇
  1986年   53165篇
  1985年   52799篇
  1984年   48577篇
  1983年   44709篇
  1982年   41947篇
  1981年   39644篇
  1980年   37351篇
  1979年   41027篇
  1978年   36528篇
  1977年   33076篇
  1976年   30324篇
  1975年   29216篇
  1974年   30759篇
  1973年   29865篇
  1972年   28082篇
排序方式: 共有10000条查询结果,搜索用时 15 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.
Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.  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