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   446篇
  免费   21篇
  国内免费   75篇
儿科学   7篇
妇产科学   5篇
基础医学   30篇
口腔科学   12篇
临床医学   58篇
内科学   92篇
皮肤病学   38篇
神经病学   7篇
特种医学   89篇
外科学   40篇
综合类   79篇
预防医学   7篇
药学   58篇
中国医学   1篇
肿瘤学   19篇
  2021年   3篇
  2019年   2篇
  2018年   8篇
  2017年   6篇
  2016年   7篇
  2015年   2篇
  2014年   2篇
  2013年   10篇
  2012年   7篇
  2011年   5篇
  2010年   22篇
  2009年   20篇
  2008年   12篇
  2007年   57篇
  2006年   29篇
  2005年   14篇
  2004年   17篇
  2003年   15篇
  2002年   7篇
  2001年   11篇
  2000年   15篇
  1999年   10篇
  1998年   25篇
  1997年   24篇
  1996年   27篇
  1995年   19篇
  1994年   11篇
  1993年   20篇
  1992年   4篇
  1991年   6篇
  1989年   13篇
  1988年   4篇
  1987年   12篇
  1986年   9篇
  1985年   15篇
  1984年   3篇
  1983年   7篇
  1982年   8篇
  1981年   10篇
  1980年   6篇
  1978年   3篇
  1977年   6篇
  1976年   5篇
  1975年   6篇
  1964年   3篇
  1963年   2篇
  1962年   2篇
  1958年   2篇
  1957年   3篇
  1955年   1篇
排序方式: 共有542条查询结果,搜索用时 15 毫秒
21.
Neurohydatidosis     
Early and non‐invasive evaluation of hydatid infestation of brain and spine is of paramount importance, especially in endemic areas. We present a spectrum of imaging findings in neurohydatidosis with a brief review of literature.  相似文献   
22.
23.
Mucormycosis is a rare fungal infection of childhood, occurring mainly in patients with chronic illnesses such as diabetes and malignancies. The fungus seldom grows in culture and confirmation of the diagnosis depends on histologic examination of infected tissues. To date, the reported natural history of the disease has been rapid progression and a fatal outcome. Therefore, the importance of early diagnosis by tissue biopsy and early treatment with surgical debridement and systemic antifungal therapy cannot be overemphasized. The pulmonary system is the most common site for mucormycosis in patients with leukemia. We report what we believe to be the first successfully treated case of isolated muscular mucormycosis occurring in a child with biphenotypic acute leukemia. The diagnosis was made promptly by tissue examination at the time of surgical debridement. The patient was also given systemic amphotericin-B therapy.   相似文献   
24.
Roxatidine acetate, a new H2 receptor antagonist, was compared with ranitidine in the treatment of duodenal ulcers in a double-blind multicentre study. Eighty-four patients with endoscopically proven duodenal ulcer were randomized to receive 150 mg roxatidine acetate or 300 mg ranitidine at bedtime. Repeat endoscopy was performed after 4 weeks (25–33 days) and if the ulcer had not healed, another endoscopy was performed after a further 4 weeks of treatment. Using per protocol analysis 73.6% of ulcers treated with roxatidine healed at 4 weeks compared to 72.2% of ulcers treated with ranitidine (P=NS). The healing rates at 8 weeks were 92% with roxatidine and 83.3% with ranitidine (P=NS). Using equivalence tests, the healing rate of roxatidine was found to be equivalent to that of ranitidine within a 20% region. Roxatidine users took significantly less antacids than ranitidine users (P < 0.05). There were no significant adverse effects due to roxatidine or ranitidine. Roxatidine is a safe effective drug in the treatment of duodenal ulcers with a healing rate comparable to that of ranitidine.  相似文献   
25.
26.
27.
亮氨酸脑啡肽的电子结构及构效关系研究   总被引:1,自引:0,他引:1  
对亮氨酸脑啡肽进行了量子化学(INDO)计算,研究其电子结构特征,讨论其活性部位、作用机理及构效关系。同吗啡和R31833进行了活性部位的电子结构与空间结构比较,推断它们的活性药效结构具有共同特点,与阿片受体相互作用时作用方式相同,作用部位有对应关系,因而具有相同的药理性质。  相似文献   
28.
Sanfilippo B syndrome is caused by a deficiency of alpha-N- acetylglucosaminidase, a lysosomal enzyme involved in the degradation of heparan sulphate. Accumulation of the substrate in lysosomes results in degeneration of the central nervous system with progressive dementia often combined with hyperactivity and aggressive behaviour. In order to clone the deficient gene, we purified the enzyme from human placenta and obtained amino acid sequence information. Alignment of one of the CNBr generated internal peptides to sequence from the database revealed the chromosomal location of the gene in the 5' upstream flanking region of the gene for 17-beta-hydroxysteroid-dehydrogenase at 17q21.1. The available DNA sequence was used to clone the cDNA coding for alpha-N- acetylglucosaminidase and analyse its gene structure. The gene is fully contained in the 5' upstream flanking region of the gene for 17-beta- hydroxysteroid-dehydrogenase and interrupted by five introns. The cDNA clone has a length of 2575 bp and encodes a protein of 743 amino acids. Chinese hamster ovary cells transfected with the cDNA construct show alpha-N-acetylglucosaminidase activity about 17-fold over background. This will allow correction studies with NAG deficient Sanfilippo B cell lines and facilitate the development of enzyme replacement therapy for these patients.   相似文献   
29.
30.
A new protoberberine alkaloid, 3‐hydroxy‐2‐methoxy‐9,10‐methylenedioxy‐8‐oxo‐protoberberine, along with three known compounds, was isolated from Rhizoma Coptidis. The new compound displayed weak antispasmodic activity against acetylcholine‐induced contraction in isolated guinea‐pig ileum with an IC50 of 83.7 μm . Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
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