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   829篇
  免费   47篇
耳鼻咽喉   8篇
儿科学   32篇
妇产科学   3篇
基础医学   59篇
口腔科学   7篇
临床医学   74篇
内科学   96篇
皮肤病学   195篇
神经病学   33篇
特种医学   44篇
外科学   127篇
综合类   17篇
一般理论   10篇
预防医学   26篇
眼科学   81篇
药学   50篇
肿瘤学   14篇
  2023年   5篇
  2022年   5篇
  2021年   18篇
  2020年   14篇
  2019年   18篇
  2018年   21篇
  2017年   27篇
  2016年   23篇
  2015年   17篇
  2014年   30篇
  2013年   30篇
  2012年   42篇
  2011年   46篇
  2010年   31篇
  2009年   17篇
  2008年   53篇
  2007年   58篇
  2006年   37篇
  2005年   49篇
  2004年   53篇
  2003年   52篇
  2002年   50篇
  2001年   34篇
  2000年   11篇
  1999年   11篇
  1998年   3篇
  1996年   5篇
  1995年   11篇
  1994年   5篇
  1993年   4篇
  1992年   8篇
  1991年   8篇
  1990年   9篇
  1989年   4篇
  1988年   6篇
  1987年   5篇
  1986年   5篇
  1985年   3篇
  1983年   2篇
  1982年   3篇
  1979年   4篇
  1976年   2篇
  1975年   4篇
  1973年   6篇
  1972年   2篇
  1971年   4篇
  1970年   2篇
  1968年   3篇
  1967年   3篇
  1966年   3篇
排序方式: 共有876条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
In the present study, we have synthesized mixed cuprous/copper oxide nanosuspensions by metallosurfactant based microemulsion technique. Three metallosurfactants were synthesized which includes two non-ionic double chained metallosurfactants with C12, C16 chains with coordinated copper i.e. Cudda and Cuhexa, respectively. Another cationic double chained metallosurfactant with loosely bound metal (Cuctac) was also prepared. The prepared metallocomplexes were characterized using FTIR, elemental analysis, and NMR. The effect of the position of metallosurfactant in microemulsion on the fabrication and properties of nanosuspensions was elucidated. In this method, no external reducing agent and capping agent were added and tween 80 acted both as reducing and stabilizing agent for the nanoparticles. The synthesized nanoparticles were characterized and it was observed that mixed copper and cuprous oxide particles are present in colloidal suspension for all the three studied metallosurfactants. The kinetics of formation of mixed copper/cuprous oxide nanosuspensions (Ns) and their stability was estimated using Uv-visible spectroscopy. Further, the binding and interactions of copper nanosuspensions with calf Thymus DNA (CT-DNA) were assessed using Uv–vis spectroscopy, circular dichroism and gel electrophoresis. Additionally, the antioxidant activity of the Cu Ns was checked using DPPH assay. The role of positive charge on nanoparticles as evaluated from Zeta potential was responsible for DNA affinity. The DNA conformational changes in the presence of nanosuspensions and relevant scavengers were investigated. Further, the anti-proliferative activity of copper Ns was assessed using HeLa cells and Cuhexa derived Ns were proved to be active with highest activity at a low concentration and were nontoxic towards normal cell lines. In summary, this work demonstrates a softer approach for the synthesis of copper nanosuspensions with a size range of 2–5?nm and evaluated the role of type and structure of metallosurfactant on size, stability of particles and anti-proliferative activity.  相似文献   
8.
9.
10.

Purpose

Hyperintensity along the ipsilateral cortical spinal tract (CST) on a diffusion weighted imaging (DWI) has been reported to may be associated with motor disability after brain infarction and can be misdiagnosed as a new infarction. However, the underlying patho-physiology related to this finding is not clear. The goal of our study was to analyze the diffusion tensor imaging (DTI) changes in patients with this hyperintensity.

Materials and methods

Eight patients (50 ± 10 years) who exhibited hyperintensity on DWI along ipsilateral CST from 3 to 21 days after stroke onset were reviewed as positive group, including 5 patients with serial DTI examinations. Twelve patients without hyperintensity during the matched examination time were classified as reference group. The apparent diffusion coefficient (ADC), fractional anisotropy (FA), and eigenvalues and their ratios (ipsilateral/contralateral value) in cerebral peduncle were measured, their correlation with motor function scale at eight months after stroke onset were evaluated.

Results

The serial examinations showed that hyperintensity could eventually disappear. Both the ipsilateral ADC and FA values were significantly decreased (p < 0.05) compared to the contralateral side. The ipsilateral FA significantly correlated with motor function scale in both groups (r = 0.875, 0.738; p = 0.004, 0.006 respectively).

Conclusions

The hyperintensity on DWI is a transient pathological process of Wallerian degeneration after ischemic stroke, its diffusion characteristics include concurrent significant decrease of ipsilateral ADC and FA. The ipsilateral FA value has the potential to predict neurological motor function outcome in such patients.  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