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   3245498篇
  免费   244876篇
  国内免费   5672篇
耳鼻咽喉   44720篇
儿科学   106207篇
妇产科学   89727篇
基础医学   473645篇
口腔科学   89756篇
临床医学   295677篇
内科学   626619篇
皮肤病学   72994篇
神经病学   259967篇
特种医学   121652篇
外国民族医学   905篇
外科学   487492篇
综合类   72049篇
现状与发展   15篇
一般理论   1197篇
预防医学   256865篇
眼科学   75754篇
药学   238709篇
  10篇
中国医学   6859篇
肿瘤学   175227篇
  2021年   25747篇
  2019年   26573篇
  2018年   36895篇
  2017年   27780篇
  2016年   31374篇
  2015年   35233篇
  2014年   50043篇
  2013年   75073篇
  2012年   102810篇
  2011年   109784篇
  2010年   65000篇
  2009年   61554篇
  2008年   102234篇
  2007年   108729篇
  2006年   109908篇
  2005年   106676篇
  2004年   102243篇
  2003年   98051篇
  2002年   94712篇
  2001年   150350篇
  2000年   154099篇
  1999年   129233篇
  1998年   37786篇
  1997年   33437篇
  1996年   33494篇
  1995年   31632篇
  1994年   29186篇
  1993年   27413篇
  1992年   99449篇
  1991年   96565篇
  1990年   93875篇
  1989年   90432篇
  1988年   83284篇
  1987年   81302篇
  1986年   76231篇
  1985年   73163篇
  1984年   54934篇
  1983年   46674篇
  1982年   28116篇
  1979年   50097篇
  1978年   35577篇
  1977年   29636篇
  1976年   28263篇
  1975年   30008篇
  1974年   36236篇
  1973年   34533篇
  1972年   32541篇
  1971年   30476篇
  1970年   28352篇
  1969年   26810篇
排序方式: 共有10000条查询结果,搜索用时 625 毫秒
891.
BACKGROUND: Abnormalities in calcium and vitamin D metabolism have been reported after bariatric surgery. The purpose of this study was to evaluate vitamin D nutritional status among morbidly obese patients before gastric bypass surgery. METHODS: We prospectively studied 279 morbidly obese patients seeking gastric bypass surgery for vitamin D nutritional status as assessed by serum 25-hydroxyvitamin D level. In addition, serum samples were analyzed for calcium, alkaline phosphatase (AP), intact parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D. RESULTS: Mean patient age was 43 +/- 9 years; 87% of the study patients were women, and 72% were white. Serum calcium and AP levels were normal in 88% and 89% of the patients, respectively. Vitamin D depletion, defined as serum 25-hydroxyvitamin D level 相似文献   
892.
893.
Veatch's Proposal May Not Work   总被引:1,自引:1,他引:0  
  相似文献   
894.
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   
895.
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   
896.
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   
897.
We report a case of a six years age girl who presented to our out patients department with the history and findings suggestive of recurrent respiratory tract infections. She was also noticed to have; non homogeneous hyper- pigmented patches on the face since three months of age, sparse hair on the scalp and eyebrows, conical peg like teeth and delayed dentition, prominent and low set ears, perpetually flexed third toe bilaterally. Axillary skin biopsy showed adenexal structures and eccrine glands in subcutaneous fat which were reduced in number. The diagnosis made was: Anhydrotic/ Hypohidrotic type of ectodermal dysplasia. Key words: Ectodermal Dysplasia, Anhidreotic, Hypohidrotic.  相似文献   
898.
899.
900.
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