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   3329819篇
  免费   261803篇
  国内免费   7692篇
耳鼻咽喉   47577篇
儿科学   103531篇
妇产科学   90597篇
基础医学   468145篇
口腔科学   94992篇
临床医学   304633篇
内科学   648623篇
皮肤病学   72140篇
神经病学   279729篇
特种医学   132418篇
外国民族医学   1186篇
外科学   496569篇
综合类   78757篇
现状与发展   7篇
一般理论   1355篇
预防医学   267834篇
眼科学   79034篇
药学   245921篇
  5篇
中国医学   7860篇
肿瘤学   178401篇
  2021年   27079篇
  2019年   27104篇
  2018年   37498篇
  2017年   28831篇
  2016年   32736篇
  2015年   37989篇
  2014年   53348篇
  2013年   78921篇
  2012年   107292篇
  2011年   112497篇
  2010年   66256篇
  2009年   62876篇
  2008年   103330篇
  2007年   108953篇
  2006年   109367篇
  2005年   106204篇
  2004年   101429篇
  2003年   97204篇
  2002年   94617篇
  2001年   151755篇
  2000年   156287篇
  1999年   131706篇
  1998年   38969篇
  1997年   35205篇
  1996年   34764篇
  1995年   33296篇
  1994年   30938篇
  1993年   28976篇
  1992年   103849篇
  1991年   99854篇
  1990年   96164篇
  1989年   92410篇
  1988年   85685篇
  1987年   84269篇
  1986年   79412篇
  1985年   75896篇
  1984年   57925篇
  1983年   49340篇
  1982年   30240篇
  1979年   53592篇
  1978年   37829篇
  1977年   31704篇
  1976年   29831篇
  1975年   31066篇
  1974年   38196篇
  1973年   36492篇
  1972年   34234篇
  1971年   31473篇
  1970年   29760篇
  1969年   27689篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Direct peroral cholangioscopy (POC) using an ultra‐slim upper endoscope is one modality of POC for intraductal endoscopic evaluation and treatment of the bile duct. Choledochoduodenostomy (CDS) is one modality of biliary bypass surgery that provides a new route to the bile duct. We carried out direct POC using an ultra‐slim upper endoscope without the use of accessories in 10 patients (four sump syndromes, three bile duct strictures and three intrahepatic duct stones) previously undergoing surgical CDS. Direct POC was successful in all patients. The use of an intraductal balloon catheter was required in one patient for advancement of the endoscope into the bile duct. Distal bile ducts with sump syndromes were cleared using baskets and water irrigation under direct POC. Cholangiocarcinoma was diagnosed in one patient with hilar bile duct stricture after cholangioscopic evaluation and a targeting forceps biopsy under direct POC. Intrahepatic duct stones were successfully extracted after intraductal fragmentation under direct POC. Oozing bleeding occurred during intraductal lithotripsy but stopped spontaneously. Direct POC using an ultra‐slim upper endoscope without the assistance of accessories can easily be carried out in patients undergoing CDS.  相似文献   
53.
54.
Dosage form is a mean used for the delivery of drug to a living body. In order to get the desired effect the drug should be delivered to its site of action at such rate and concentration to achieve the maximum therapeutic effect and minimum adverse effect. Since oral route is still widely accepted route but having a common drawback of difficulty in swallowing of tablets and capsules. Therefore a lot of research has been done on novel drug delivery systems. This review is about oral dispersible tablets a novel approach in drug delivery systems that are now a day''s more focused in formulation world, and laid a new path that, helped the patients to build their compliance level with the therapy, also reduced the cost and ease the administration especially in case of pediatrics and geriatrics. Quick absorption, rapid onset of action and reduction in drug loss properties are the basic advantages of this dosage form.  相似文献   
55.
56.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
57.
58.
59.
Hepatic NADPH-cytochrome P450 oxidoreductase null (HRN?) mice exhibit normal hepatic and extrahepatic biotransformation enzyme activities when compared to wild-type (WT) mice, but express no functional hepatic cytochrome P450 activities. When incubated in vitro with [14C]-diclofenac, liver microsomes from WT mice exhibited extensive biotransformation to oxidative and glucuronide metabolites and covalent binding to proteins was also observed. In contrast, whereas glucuronide conjugates and a quinone-imine metabolite were formed when [14C]-diclofenac was incubated with HRN? mouse liver, only small quantities of P450-derived oxidative metabolites were produced in these samples and covalent binding to proteins was not observed. Livers from vehicle-treated HRN? mice exhibited enhanced lipid accumulation, bile duct proliferation, hepatocellular degeneration and necrosis and inflammatory cell infiltration, which were not present in livers from WT mice. Elevated liver-derived alanine aminotransferase, glutamate dehydrogenase and alkaline phosphatase activities were also observed in plasma from HRN? mice. When treated orally with diclofenac for 7 days, at 30 mg/kg/day, the severities of the abnormal liver histopathology and plasma liver enzyme findings in HRN? mice were reduced markedly. Oral diclofenac administration did not alter the liver histopathology or elevate plasma enzyme activities of WT mice. These findings indicate that HRN? mice are valuable for exploration of the role played by hepatic P450s in drug biotransformation, but poorly suited to investigations of drug-induced liver toxicity. Nevertheless, studies in HRN? mice could provide novel insights into the role played by inflammation in liver injury and may aid the evaluation of new strategies for its treatment.  相似文献   
60.
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