全文获取类型
收费全文 | 353篇 |
免费 | 80篇 |
国内免费 | 51篇 |
专业分类
化学 | 236篇 |
晶体学 | 8篇 |
力学 | 11篇 |
数学 | 2篇 |
物理学 | 173篇 |
综合类 | 54篇 |
出版年
2024年 | 1篇 |
2023年 | 14篇 |
2022年 | 19篇 |
2021年 | 23篇 |
2020年 | 16篇 |
2019年 | 6篇 |
2018年 | 16篇 |
2017年 | 15篇 |
2016年 | 20篇 |
2015年 | 14篇 |
2014年 | 19篇 |
2013年 | 43篇 |
2012年 | 28篇 |
2011年 | 21篇 |
2010年 | 15篇 |
2009年 | 12篇 |
2008年 | 21篇 |
2007年 | 20篇 |
2006年 | 16篇 |
2005年 | 15篇 |
2004年 | 21篇 |
2003年 | 15篇 |
2002年 | 14篇 |
2001年 | 6篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
排序方式: 共有484条查询结果,搜索用时 15 毫秒
101.
102.
Jacek Goworek Andrzej Dąbrowski Mieczysław Jaroniec Jerzy Garbacz 《Monatshefte für Chemie / Chemical Monthly》1982,113(8-9):925-932
The adsorption isotherms of methyl, ethyl,n-propyl andn-butyl acetates from benzene andn-heptane on silica gel have been measured at 298 K. A bilayer model of surface phase has been used to interpret these experimental data. It has been shown that the chain length of the hydrocarbon part of the ester and the solvent affinity to the adsorbent influence the structure of the surface phase. Moreover, this structure is also determined by energetic heterogeneity of the adsorbent surface.
Die Anwendung eines Zweischicht-Adsorptionsmodells zum Verständnis der Adsorption von Estern ausn-Heptan- und Benzollösungen auf Kieselgel
Zusammenfassung Es wurden die Adsorptionsisothermen der Methyl-, Ethyl-,n-Propyl undn-Butylacetate in Benzol undn-Heptanlösungen auf Kieselgel bei 298 K gemessen. Zur Interpretation der experimentellen Daten ist ein Zweischicht-Modell für die Oberflächenphase benutzt worden. Es wurde gezeigt, daß die Länge der Esterkohlenwasserstoffkette und die Aktivität des Lösungsmittels Einfluß auf die Struktur der Oberflächenform haben. Außerdem ist diese Struktur durch energetische Inhomogenität der Adsorbensoberfläche bestimmt.相似文献
103.
Mario Suwalsky Beryl NorrisTamas Kiss Paolo Zatta 《Coordination chemistry reviews》2002,228(2):285-295
Aluminum, a very abundant metal, might play an important role in several pathologies which could be related to its interactions with cell membranes. Although the effects of Al(III) on biological membranes have been extensively described, direct information concerning the molecular basis of its biological activity is rather scarce. One reason for this lack of molecular information is the ill-defined chemical speciation of the metal compounds utilized in toxicological experimental protocols. Another is the complex molecular structure of cell membranes. For this reason, molecular models consisting in phospholipid bilayers are commonly used. In this review the interaction of four Al(III) compounds with phospholipid bilayers built-up of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) and their effects on ion channels present in isolated toad skins are discussed. The aluminum compounds are Al(acac)3, AlCl3, AlF3 and the Al-citrate complex [K5Al(C6H4O7)2]. It is concluded that they interact with and produce different structural and functional effects on the model and biological membranes. X-ray diffraction revealed that AlCl3 (1 mM) induced the most damaging effects to both DMPC and DMPE bilayers whereas the Al-citrate complex caused only slight perturbation, the effects of Al(acac)3 and AlF3 being intermediate. The inhibitory effects on the isolated skin, in descending order, were (100 μM): AlCl3, possibly by indirect and direct inactivation of Na+ channels and/or perturbation of an ATPase; AlF3, by direct inactivation of the Na+ channel and mild ATPase inhibition; Al-citrate, by decrease of Na+ permeability, and lastly, Al(acac)3, which decreased Na+ transport only at far higher concentration (250 μM). 相似文献
104.
Molecular dynamics study of the mechanical characteristics of Ni/Cu bilayer using nanoindentation
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
<正>In the present work,a three-dimensional molecular dynamics simulation is carried out to perform the nanoindentation experiment on Ni single crystal.The substrate indenter system is modeled using hybrid interatomic potentials including the many-body potential embedded atom method(EAM),and two-body morse potential.To simulate the indentation process,a spherical indenter(diameter = 80 A,1 A=0.1 nm) is chosen.The results show that the mechanical behaviour of a monolithic Ni is not affected by crystalline orientation.To elucidate the effect of a heterogeneous interface, three bilayer interface systems are constructed,namely Ni(100)/Cu(111),Ni(110)/Cu(111),and Ni(111)/Cu(111).The simulations along these systems clearly describe that mechanical behaviour directly depends on the lattice mismatch. The interface with the smaller mismatch between the specified crystal planes is proved to be harder and vice versa.To describe the relationship between film thickness and interface effect,we choose various values of film thickness ranging from 20 A to 50 A to perform the nanoindentation experiment.It is observed that the interface is significant only for the relatively small thickness of film and the separation between interface and the indenter tip.It is shown that with the increase in film thickness,the mechanical behaviour of the film shifts more toward that of monolithic material. 相似文献
105.
106.
Stephen L. De Wall Eric S. Meadows Clare L. Murray Hossein Shabany George W. Gokel 《Supramolecular chemistry》2013,25(1):13-22
Abstract A family of tris(macrocyclic) compounds of the form sidearm<N18N>Cn<N18N>Cn<N18N>sidearm, has been prepared, characterized chemically, and assayed by dynamic 23Na-NMR for the ability to transport sodium cations in a mixed phosphatidylglycerol/phosphatidylcholine vesicle system. A number of control experiments have been conducted that reinforce the hypothesis that cation transport occurs by a channel mechanism. The tris(macrocycle) channels proved to be functional at a level of 25–50% of that found for the natural pentadecapeptide channel gramicidin. Fluorescence data confirm the expected position of the channel within the bilayer. 相似文献
107.
Two metal–organic supramolecular compounds, [Mg(H2O)6]·2FcCO2·2H2O (1) and [Mg(H2O)6]·2FcCOC6H4CO2·2H2O (2), were prepared by solvothermal synthesis. The solids exhibit non-covalent self-assembly and layered structures with unprecedented inverse lipid-like bilayer arrangements. Further investigations revealed that the layered structures were sensitive to pH changes. The proposed synthesis method in this report would allow development of new types of pH-responsive materials. 相似文献
108.
固体支撑的双层类脂膜不仅是研究和模拟发生在生物膜上各种过程的重要模型,而且也成为研制生物分子电子器件的重要工具.在固体支撑的双层类脂膜中,金/硫醇-类脂双层膜以其缺陷少、稳定性高等特性而倍受关注[1].本文报道了修饰7,7,8,8-四氰基奎诺二甲烷(... 相似文献
109.
《中国物理 B》2021,30(7):77103-077103
Owing to the interaction between the layers, the twisted bilayer two-dimensional(2 D) materials exhibit numerous unique optical and electronic properties different from the monolayer counterpart, and have attracted tremendous interests in current physical research community. By means of first-principles and tight-binding model calculations, the electronic properties of twisted bilayer biphenylene carbon(BPC) are systematically investigated in this paper. The results indicate that the effect of twist will not only leads to a phase transition from semiconductor to metal, but also an adjustable band gap in BPC(0 me V to 120 me V depending on the twist angle). Moreover, unlike the twisted bilayer graphene(TBG), the flat bands in twisted BPC are no longer restricted by "magic angles", i.e., abnormal flat bands could be appeared as well at several specific large angles in addition to the small angles. The charge density of these flat bands possesses different local modes, indicating that they might be derived from different stacked modes and host different properties. The exotic physical properties presented in this work foreshow twisted BPC a promising material for the application of terahertz and infrared photodetectors and the exploration of strong correlation. 相似文献
110.
In this paper we study the bilayer quantum Hall (QH) effect on a noncommutative phase space (NCPS). By using perturbation theory, we calculate the energy spectrum, eigenfunction, Hall current, and Hall conductivity of the bilayer QH system, and express them in terms of noncommutative parameters θ and θ^-, respectively. In our calculation, we assume that these parameters vary from laver to laver. 相似文献