全文获取类型
收费全文 | 217篇 |
免费 | 2篇 |
国内免费 | 3篇 |
专业分类
化学 | 112篇 |
晶体学 | 1篇 |
力学 | 16篇 |
综合类 | 1篇 |
数学 | 18篇 |
物理学 | 74篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 13篇 |
2012年 | 14篇 |
2011年 | 13篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 11篇 |
2007年 | 11篇 |
2006年 | 8篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 14篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有222条查询结果,搜索用时 31 毫秒
131.
An approach to constructing a biased potential for hyperdynamic simulation of atomic systems is considered. Using this approach, the diffusion of an atom adsorbed on the surface of a two-dimensional crystal and a vacancy in the bulk of the crystal are simulated. The influence of the variation in the potential barriers due to thermal vibrations of atoms on the results of calculations is discussed. It is shown that the bias of the potential in the hyperdynamic simulation makes it possible to obtain statistical samples of transitions of atomic systems between states, similar to those given by classical molecular dynamics. However, hyperdynamics significantly accelerates computations in comparison with molecular dynamics in the case of temperature-activated transitions and the associated processes in atomic systems. 相似文献
132.
H. Abramowicz G. Hansl-Kozanecki J. May P. Palazzi A. Para F. Ranjard A. Savoy-Navarro D. Schlatter J. Steinberger H. Taureg W. von Rüden H. Wahl S. Whitaker J. Wotschack H. Blümer P. Buchholz J. Duda F. Eisele K. Kleinknecht J. Knobloch H. Lierl B. Pszola B. Renk F. Dydak J. G. H. de Groot T. Flottmann C. Geweniger V. Hepp J. Królikowski K. Tittel P. Debu C. Guyot J. P. Merlo P. Perez B. Peyaud J. Rander J. P. Schuller R. Turlay 《Zeitschrift fur Physik C Particles and Fields》1984,25(1):29-43
The CDHS neutrino detector has been used to measure events originating in a tank of liquid hydrogen and in the iron of the detector. Total cross-sections, differential cross-sections, and structure functions are given for hydrogen and compared with those in iron. The measurements are in agreement with the expectations of the quark parton model. No significant differences indicative of nuclear binding effects in corresponding structure functions of protons and iron are observed. This may be of special interest in the case of the sea structure functions, since large differences are expected in some models. 相似文献
133.
The effect of vacancies on the electronic transport in the ZnCr2−xNixSe4 paramagnetic single crystals is considered. For this purpose, the structure refinements, the high temperature electrical conductivity and the thermoelectric power measurements as well as the calculations of the vacancy model parameters were used. The electrical measurements have been done in the temperature range from 290 to 520 K for single crystals with x=0.001, 0.05, and 0.065. The above investigations provide evidence for polaron conduction in defective spinel materials. In particular: (1) at high temperatures a linear dependence between thermopower S and the electrical resistivity (ln ρ), a characteristic of small polarons, was observed, (2) an origin of small polarons in this case could be associated with a crystalline distortion, which is characterized by larger values of the anion parameter than u=0.375, which describes an ideal spinel structure, and (3) a large defectiveness, which is identified by the large value of the vacancy parameter of about β=11.5%. These effects are explained in terms of a polaron mechanism of the electrical conductivity including structural defects. 相似文献
134.
Yu. V. Fedoseeva T. A. Duda A. G. Kurenya A. V. Gusel’nikov K. S. Zhuravlev O. Yu. Vilkov L. G. Bulusheva A. V. Okotrub 《Journal of Structural Chemistry》2017,58(5):876-884
The composition and electronic structure of cadmium sulfide (CdS) nanoparticles formed by the Langmuir–Blodgett (LB) technique on clean silicon wafers and the surface of vertically aligned carbon nanotube (CNT) arrays are studied by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The samples were annealed in a vacuum at 175 °C and 225 °C to remove the organic matrix of the LB film. From the analysis of the XPS data the increased concentration of sulfate groups on the surface of CdS nanoparticles formed on CNTs and the electron density transfer from CdS to CNTs are determined. An increase in the LB film annealing temperature causes an increase in the degree of crystallinity and the CdS crystallite size and a decrease in the photoluminescence intensity of a CdS–CNT hybrid. 相似文献
135.
There exist experimental evidences that the structure and extension of colloidal aggregates in suspensions change dramatically with temperature. This results in an associated change in the suspension rheology. Experimental studies of the inhibitor applications to control the particle clustering have revealed some unexpected tendencies. Namely, the heating of colloidal suspensions has provoked either extension or reduction of the colloidal aggregates. To elucidate the origin of this behavior, we investigate the influence of temperature on the stabilizing effect of the inhibitor, applying an associative two-component fluid model. Our results of the canonical Monte Carlo simulations indicate that the anomalous effect of the temperature may not be necessarily explained by the temperature dependent changes in the inhibitor tail conformation, as has been suggested recently by Won et al. [Langmuir 21, 924 (2005)]. We show that the competition between colloid-colloid and colloid-inhibitor associations, which, in turn, depends on the temperature and the relative concentrations, may be one of the main reasons for the unexpected temperature dependence of inhibitor efficacy. 相似文献
136.
A new method for characterizing the deformable porous materials with noncritical adsorption probes is proposed. The mechanism is based on driving the adsorbate through a sequence of constrained equilibrium states with the insertion isotherms forming a pseudocritical point or a van der Waals-type loop. In the framework of a perturbation theory and Monte Carlo simulations we have found a link between the loop parameters and the host morphology. This allows one to characterize porous matrices through analyzing a shift of the pseudocritical point and a shape of the pseudospinodals. 相似文献
137.
Adam Kowalski Andrzej Duda Stanislaw Penczek 《Macromolecular rapid communications》1998,19(11):567-572
Kinetics of polymerization of ε-caprolactone (CL) initiated with tin(II) octoate (Sn(Oct)2) in THF as a solvent at 80°C was studied. The results strongly indicate that polymerization initiated with Sn(Oct)2 proceeds on the tin(II)-alkoxide bond and are not compatible with a mechanism in which propagation was proposed to proceed by a nucleophilic attack of the … OH ended macromolecules on the monomer-Sn(Oct)2 complex. 相似文献
138.
V. Muralidharan Anil Tihminlioglu Olivia Antelmann J. Larry Duda Ronald P. Danner Andre De Haan 《Journal of Polymer Science.Polymer Physics》1998,36(10):1713-1719
Self-diffusion and partition coefficients were measured for two commercial ethylene–propylene-diene copolymers (EPDM) and five solvents at infinite dilution using inverse gas chromatography. Mutual diffusion coefficients for solvents in EPDM also were measured for finite concentration using gravimetric sorption for three of the solvents. From the inverse gas chromatography experimental values for self-diffusion coefficients were obtained. Free-volume parameters were obtained through regression of the self-diffusion coefficient as a function of temperature. Mutual diffusion coefficients as a function of concentration were predicted using free volume theory and compared with experimental data obtained using gravimetric sorption. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1713–1719, 1998 相似文献
139.
140.
We have studied a model of a hard sphere fluid adsorbed in a cylindrical pore filled with quenched disordered matrix of hard
sphere particles using Grand canonical Monte Carlo simulations. The interactions between matrix species and pore walls are
assumed of a hard sphere type. However, the pore walls exert a short-range attraction upon adsorbed fluid particles. We discuss
the adsorption isotherms and the density profiles of fluid particles in pores with different microporosity for several values
of the pore radius. We have observed that like in homogeneous microporous media the adsorption increases with increasing porosity.
However, trends of behavior of the isotherms also reflect layering of adsorbed fluid. The data obtained in this study may
serve as a benchmark for the development of the theory of confined quenched-annealed systems and for computer simulation investigation
of models permitting phase transitions in pores.
This project has been supported in parts by DGAPA of the UNAM under research grant IN111597, by the National Council for Science
and Technology (CONACyT), grant No. 25301-E. 相似文献