全文获取类型
收费全文 | 77篇 |
免费 | 3篇 |
国内免费 | 15篇 |
专业分类
化学 | 61篇 |
力学 | 12篇 |
数学 | 17篇 |
物理学 | 5篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 5篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有95条查询结果,搜索用时 15 毫秒
1.
Zhong‐Zhen Yu Mingshu Yang Qingxin Zhang Chungui Zhao Yiu‐Wing Mai 《Journal of Polymer Science.Polymer Physics》2003,41(11):1234-1243
Nylon‐66 nanocomposites were prepared by melt‐compounding nylon‐66 with an alkyl ammonium surfactant pretreated montmorillonite (MMT). The thermal stability of the organic MMT powders was measured by thermogravimetric analysis. The decomposition of the surfactant on the MMT occurred from 200 to 500 °C. The low onset decomposition temperature of the organic MMT is one shortcoming when it is used to prepare polymer nanocomposites at high melt‐compounding temperatures. To provide greater property enhancement and better thermal stability of the polymer/MMT nanocomposites, it is necessary to develop MMT modified with more thermally stable surfactants. The dispersion and spatial distribution of the organic MMT layers in the nylon‐66 matrix were characterized by X‐ray diffraction. The organic MMT layers were exfoliated but not randomly dispersed in the nylon‐66 matrix. A model was proposed to describe the spatial distribution of the organic MMT layers in an injection‐molded rectangular bar of nylon‐66/organic MMT nanocomposites. Most organic MMT layers were oriented in the injection‐molding direction. Layers near the four surfaces of the bar were parallel to their corresponding surfaces; whereas those in the bulk differed from the near‐surface layers and rotated themselves about the injection‐molding direction. The influence of the spatial distribution of the organic MMT on crystallization of nylon‐66 was also investigated. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1234–1243, 2003 相似文献
2.
Mingshu Chen 《Surface science》2006,600(19):L255
In this letter, atomically resolved scanning tunneling microscopic (STM) images obtained from monolayer SiO2/Mo(1 1 2) are presented. The results are consistent with a previously proposed structural model of isolated [SiO4] units based on vibrational features observed by high-resolution electron energy loss spectroscopy (HREELS) and infrared reflection-absorption spectroscopy (IRAS), and oxygen species identified by ultra-violet photoemission spectroscopy (UPS). These results are inconsistent with a structural model that assumes a two-dimensional (2-D) [Si-O-Si] network. These data illustrate that a metal substrate, although coated with an oxide thin layer, can be directly imaged at the atomic-scale with STM. 相似文献
3.
尼龙66/蒙脱土复合材料结晶行为的研究 总被引:8,自引:0,他引:8
在密炼机中采用熔融共混法制备蒙脱土重量分数为 2 5 %、4 5 %的尼龙 6 6 /蒙脱土复合材料 .通过DSC法对非等温结晶行为及在 2 2 8~ 2 4 0℃范围内的等温结晶行为进行研究 ,并与纯尼龙 6 6进行比较 .从其等温和非等温结晶行为的研究表明 ,蒙脱土起成核剂的作用 ,它的填入使尼龙 6 6结晶速率提高 ,但填料与基体间的相互作用使其链段运动困难 ,结晶活化能提高 ;在研究的填料含量变化范围内 ,结晶行为变化不大 ,并且找到该复合材料在 2 2 8~ 2 34℃范围结晶对温度的不敏感区 ;对非等温结晶过程分析 ,刘结平 莫志深方程是适用的 ,而Ozawa方程则是不适用的 . 相似文献
4.
5.
6.
CAO Mengyao SUN Yueyang XIAO Mingshu LI Li LIU Xiaohui JIN Hong PEI Hao 《高等学校化学研究》2020,36(2):254-260
In spite of great development in nanoparticle-based drug delivery systems(DDSs)for improved therapeutic efficacy,it remains challenging for effective delivery of chemotherapeutic drugs to targeted tumor cells.In this work,we report a triangle DNA origami as targeted DDS for cancer therapy.DNA origami shows excellent biocompatibility and stability in cell culture medium for 24 h.In addition,the DNA origami structures conjugated with multivalent aptamers enable for efficient delivery of anticancer drug doxorubicin(Dox)into targeted cancer cell due to their targeting function,reducing side effects associated with nonspecific distribution.Moreover,we also demonstrated that the multivalent aptamer-modified DNA origami loading Dox exhibits prominent therapeutic efficacy in vitro.Accordingly,this work provides a good paradigm for the development of DNA origami nanostructure-based targeted DDS for cancer therapy. 相似文献
7.
8.
Huaili Qin Zhenguang Zhang Meng Feng Fangling Gong Shimin Zhang Mingshu Yang 《Journal of Polymer Science.Polymer Physics》2004,42(16):3006-3012
The photo‐oxidative degradation of polyethylene/montmorillonite (PE/MMT) nanocomposite and microcomposite has been investigated. It has been found that the rate of photo‐oxidative degradation of PE/MMT nanocomposite and PE/Mn+MMT (where Mn+ stands for multivalent transition metal cation) microcomposites is much faster than that of pure PE. For the PE/MMT nanocomposite, the acceleration of photo‐oxidative degradation is due to the influence of MMT and ammonium ion, in which the influence of ammonium is primary. The decomposition of ammonium ion may create acidic sites on layered silicates; meanwhile, the complex crystallographic structure and habit of clay minerals could also result in some active sites. The reversible photo‐redox reaction of transition metal cations has a catalytic effect in the degradation of the polymer matrix. All these catalytic active sites can accept single electrons from donor molecules of polymer matrix and induce the formation of free radical upon UV irradiation. The generation of free radical leads to the oxidization and break of molecular chain. Thus, the materials suffer degradation and their mechanical strength decreases. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3006–3012, 2004 相似文献
9.
Dulin Kong Qinghe Wang Zhongxiang Zhu Xianghui Wang Zaifeng Shi Qiang Lin Mingshu Wu 《Tetrahedron letters》2017,58(27):2644-2647
A one-pot, three-component condensation reaction of 8-quinolinol, 2-thiobarbituric acid and isatins or aldehydes in water to give novel barbituroquinoline derivatives for the first time, is described. The reaction is free of catalysts and toxic solvents, operating under mild conditions and allows for ease of product isolation, making it more environmentally friendly and suitable for large-scale operations. 相似文献
10.
Mingshu CHEN 《物理化学学报》2017,33(12):2424-2437
明确催化剂的活性位本质和构建多相催化的结构和反应性能之间的准确关系是催化基础研究的重点,表面科学研究基于丰富的表征测试手段能够较好地在分子原子水平测定表面结构以明确催化剂活性位本质,并通过高压原位反应池测定相关催化反应性能,获得较可靠的催化剂构效关系。本文简要总结了近年来本人参与的几个模型催化研究例子,包括贵金属表面上CO和烷烃催化氧化的活性表面、纳米Au膜的制备和CO氧化的催化活性位、VO_x/Pt(111)上丙烷氧化的协同作用、Au Pd合金上醋酸乙烯酯合成Au的助催化作用、模型氧化物上纳米Pt的庚烷脱氢环化制甲苯的粒径关系等,以及相关模型催化研究技术的进展。 相似文献