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   104篇
  免费   6篇
儿科学   2篇
基础医学   7篇
口腔科学   1篇
临床医学   18篇
内科学   26篇
皮肤病学   8篇
神经病学   7篇
外科学   19篇
综合类   2篇
预防医学   1篇
药学   14篇
中国医学   3篇
肿瘤学   2篇
  2021年   2篇
  2016年   3篇
  2015年   3篇
  2014年   3篇
  2013年   2篇
  2012年   2篇
  2011年   2篇
  2010年   4篇
  2009年   7篇
  2008年   4篇
  2007年   4篇
  2006年   10篇
  2005年   2篇
  2004年   6篇
  2003年   3篇
  2002年   5篇
  2001年   1篇
  1999年   2篇
  1998年   4篇
  1997年   3篇
  1996年   7篇
  1995年   2篇
  1994年   3篇
  1993年   1篇
  1992年   3篇
  1990年   4篇
  1989年   2篇
  1988年   1篇
  1986年   2篇
  1984年   1篇
  1982年   1篇
  1959年   1篇
  1958年   3篇
  1957年   2篇
  1956年   3篇
  1955年   1篇
  1954年   1篇
排序方式: 共有110条查询结果,搜索用时 203 毫秒
1.
2.
Cholestatic hepatocellular carcinoma, which grows into the bile duct and causes obstructive jaundice, is rare and difficult to diagnose. A case is presented in which cholestatic hepatocellular carcinoma was detected by deposit of Lipiodol. This is also the first case that was successfully treated by endoscopic retrograde biliary drainage and transcatheter arterial embolization.  相似文献   
3.
丁香水溶性化学成分的研究   总被引:2,自引:0,他引:2  
目的:研究丁香水溶性化学成分。方法:利用HP-20大孔吸附树脂、反相硅胶柱色谱、反相制备薄层色谱、制备型反相高效液相色谱进行分离,NMR和MS等方法进行结构鉴定。结果:从丁香干燥花蕾的水提物中分离鉴定了5个化合物,分别为槲皮素-3-O-葡萄糖醛酸苷(1),槲皮素-3-O-葡萄糖醛酸苷6″-甲酯(2),槲皮素-3-O-葡萄糖苷(3),丁香酚-β-芸香糖苷(4),杨梅酮(5)。结论:化合物1~4为首次从丁香属植物中分离得到。  相似文献   
4.
中日产川芎的matK、ITS基因序列及其物种间的亲缘关系   总被引:9,自引:0,他引:9  
目的分析中国产川芎Ligusticum chuanxiong Hort.及日本产川芎Cnidium officinale Makino的核基因组ITS和叶绿体基因组matK序列,为探讨中日产川芎物种间的亲缘关系提供分子依据。方法采用PCR直接测序技术测定川芎和日本川芎的ITS基因和matK基因核苷酸序列并作序列变异分析。结果川芎和日本川芎的matK序列长度均为1268 bp,编码422个氨基酸。ITS1-5.8S-ITS2序列长度均为699 bp,其中18S rRNA基因3′端序列54 bp,ITS1序列215 bp,5.8S rRNA基因序列162 bp,ITS2序列222 bp,26S rRNA基因5′端序列46 bp。根据排序比较,川芎原植物与其商品药材间的matK基因和ITS基因序列完全相同,而川芎与日本川芎间matK基因则仅有1个变异位点,即在上游959 nt处1个转换替代(T→C),反映在氨基酸序列则发生一个非同义取代V(GTG)→A(GCG);ITS基因也仅有1个变异位点,即在ITS1上游54 nt处1个转换替代(T→C)。结论通过进化速率较快的基因序列同源性分析,基本可以认为中日所产川芎基原一致,日本川芎学名似应改为Ligusticum chuanxiong Hort.。  相似文献   
5.
6.
A conformation analysis of tetrapeptide in DMSO was carried out by the Monte Carlo simulation including the solvent effect in the energy function. The lowest energy conformations in the zwitterionic and cationic states are a similar compact form, in which the two aromatic rings are close to each other. The distance distributions between the specified atoms in the molecule show that most conformations in the local energy minima are similar to this folded conformation, although there is another type of conformation of interest, which has an extended form with the two separate aromatic rings. Such results are consistent with the NMR and CD experiments, and suggest that the compact form of tetragastrin is essential as a biological active conformation. The folded structure is stabilized by the solute-solvent interaction. In particular, the non-bonding interactions between the solute and solvent molecules cause a folding effect on the molecular conformation in total. This study is a first case taking account of the solvent effect into the conformation analysis of tetragastrin.  相似文献   
7.
8.
MDCT/MRI Fusion for the Guidance of VT Ablation . Background: Delayed enhancement (DE) MRI can assess the fibrotic substrate of scar‐related VT. MDCT has the advantage of inframillimetric spatial resolution and better 3D reconstructions. We sought to evaluate the feasibility and usefulness of integrating merged MDCT/MRI data in 3D‐mapping systems for structure–function assessment and multimodal guidance of VT mapping and ablation. Methods: Nine patients, including 3 ischemic cardiomyopathy (ICM), 3 nonischemic cardiomyopathy (NICM), 2 myocarditis, and 1 redo procedure for idiopathic VT, underwent MRI and MDCT before VT ablation. Merged MRI/MDCT data were integrated in 3D‐mapping systems and registered to high‐density endocardial and epicardial maps. Low‐voltage areas (<1.5 mV) and local abnormal ventricular activities (LAVA) during sinus rhythm were correlated to DE at MRI, and wall‐thinning (WT) at MDCT. Results: Endocardium and epicardium were mapped with 391 ± 388 and 1098 ± 734 points per map, respectively. Registration of MDCT allowed visualization of coronary arteries during epicardial mapping/ablation. In the idiopathic patient, integration of MRI data identified previously ablated regions. In ICM patients, both DE at MRI and WT at MDCT matched areas of low voltage (overlap 94 ± 6% and 79 ± 5%, respectively). In NICM patients, wall‐thinning areas matched areas of low voltage (overlap 63 ± 21%). In patients with myocarditis, subepicardial DE matched areas of epicardial low voltage (overlap 92 ± 12%). A total number of 266 LAVA sites were found in 7/9 patients. All LAVA sites were associated to structural substrate at imaging (90% inside, 100% within 18 mm). Conclusion: The integration of merged MDCT and DEMRI data is feasible and allows combining substrate assessment with high‐spatial resolution to better define structure–function relationship in scar‐related VT. (J Cardiovasc Electrophysiol, Vol. 24, pp. 419‐426, April 2013)  相似文献   
9.
Abstract: A 40-year-old man was admitted to our hospital with persistent fever, generalized lymphadenopathy and hepatosplenoamegaly. Immunological examination demonstrated high titers of several anti-Epstein-Barr virus (EBV) antibodies, including anti-viral capsid antigens 1gG-antibody 1: 20, 480, anti-early antigens-DR IgG-antibody 1: 5, 120, and reduced activity of EBV-specific cytotoxic T lymphocytes. Laparoscopic features resembled those of chronic active viral hepatitis, including an uneven surface appearance and diffuse hepatic enlargement. Histopathological examination of a liver biopsy specimen showed inflammatory cell infiltration along sinusoidal surfaces (single file appearance) and enlarged portal areas with intralobular punched-out necrosis. The diagnosis was confirmed by detecting the EB viral genome in serum. Despite treatments with natural alpha-interferon, adenosine arabinocide and recombinant human interleukin-2, the patient died of progressive hepatic failure.  相似文献   
10.
Cognitive deficits caused by dementing illnesses are chronic and progressive problems, which should be tackled both by biological and non‐biological approaches. Among the various techniques of non‐biological approaches (cognitive rehabilitation), centered is cognitive training intervention for individuals with dementia. Cognitive training is further divided into two different types of setting: group and individualized. Among group training techniques, the reality orientation training and day care/day services are known to have evidence‐based efficacy. Individually tailored cognitive training aims to directly and explicitly improve cognitive functioning of people with dementia specifically in the early stages. Increasing evidence demonstrates the efficacy of various individualized training programs for dementia, including Alzheimer's disease (AD). Specifically, three techniques, known as spaced retrieval, dual cognitive support and procedural memory training, have shown promise in their ability to enhance learning in people with dementia. In addition, recent studies have suggested that a combination of pharmacotherapy and cognitive training may benefit individuals with AD. Cognitive training appears to be particularly effective for people with mild memory impairment who are on cholinergic treatment. It is now widely accepted that the theoretical framework of ‘errorless learning’ is also a guiding principle in the realm of cognitive training for people with dementia. Although the effect of factors, namely effort (effortful vs effortless) and stimulus features (perceptual vs conceptual), has not been fully determined, error elimination during learning sessions is essential for favorable outcomes.  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