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   2427281篇
  免费   180778篇
  国内免费   5374篇
耳鼻咽喉   32046篇
儿科学   81209篇
妇产科学   67090篇
基础医学   347517篇
口腔科学   70290篇
临床医学   219549篇
内科学   471024篇
皮肤病学   55129篇
神经病学   190302篇
特种医学   92106篇
外国民族医学   528篇
外科学   366892篇
综合类   56857篇
现状与发展   4篇
一般理论   878篇
预防医学   184249篇
眼科学   57590篇
药学   177107篇
  9篇
中国医学   5779篇
肿瘤学   137278篇
  2019年   18767篇
  2018年   27281篇
  2017年   20804篇
  2016年   23036篇
  2015年   26195篇
  2014年   36279篇
  2013年   53967篇
  2012年   73497篇
  2011年   77798篇
  2010年   46184篇
  2009年   43258篇
  2008年   72473篇
  2007年   77166篇
  2006年   77868篇
  2005年   74633篇
  2004年   72416篇
  2003年   68958篇
  2002年   66612篇
  2001年   122113篇
  2000年   125046篇
  1999年   104010篇
  1998年   27947篇
  1997年   24692篇
  1996年   24724篇
  1995年   23721篇
  1994年   21835篇
  1993年   20268篇
  1992年   80069篇
  1991年   77646篇
  1990年   75241篇
  1989年   72480篇
  1988年   65858篇
  1987年   64962篇
  1986年   61095篇
  1985年   58271篇
  1984年   43075篇
  1983年   36531篇
  1982年   21076篇
  1981年   18870篇
  1979年   38595篇
  1978年   27158篇
  1977年   23133篇
  1976年   21608篇
  1975年   22715篇
  1974年   27562篇
  1973年   26500篇
  1972年   24529篇
  1971年   22706篇
  1970年   21123篇
  1969年   19769篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
61.
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   
62.
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   
63.
64.
65.
Bipolar disorder (BD) is a common psychiatric mood disorder affecting more than 1-2% of the general population of different European countries. Unfortunately, there is no objective laboratory-based test to aid BD diagnosis or monitor its progression, and little is known about the molecular basis of BD. Here, we performed a comparative proteomic study to identify differentially expressed plasma proteins in various BD mood states (depressed BD, manic BD, and euthymic BD) relative to healthy controls. A total of 10 euthymic BD, 20 depressed BD, 15 manic BD, and 20 demographically matched healthy control subjects were recruited. Seven high-abundance proteins were immunodepleted in plasma samples from the 4 experimental groups, which were then subjected to proteome-wide expression profiling by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight tandem mass spectrometry. Proteomic results were validated by immunoblotting and bioinformatically analyzed using MetaCore. From a total of 32 proteins identified with 1.5-fold changes in expression compared with healthy controls, 16 proteins were perturbed in BD independent of mood state, while 16 proteins were specifically associated with particular BD mood states. Two mood-independent differential proteins, apolipoprotein (Apo) A1 and Apo L1, suggest that BD pathophysiology may be associated with early perturbations in lipid metabolism. Moreover, down-regulation of one mood-dependent protein, carbonic anhydrase 1 (CA-1), suggests it may be involved in the pathophysiology of depressive episodes in BD. Thus, BD pathophysiology may be associated with early perturbations in lipid metabolism that are independent of mood state, while CA-1 may be involved in the pathophysiology of depressive episodes.  相似文献   
66.
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   
67.
68.
69.
70.
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