全文获取类型
收费全文 | 621篇 |
免费 | 5篇 |
国内免费 | 11篇 |
专业分类
化学 | 237篇 |
晶体学 | 2篇 |
力学 | 15篇 |
数学 | 132篇 |
物理学 | 251篇 |
出版年
2020年 | 4篇 |
2019年 | 4篇 |
2017年 | 7篇 |
2016年 | 13篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 27篇 |
2012年 | 19篇 |
2011年 | 25篇 |
2010年 | 16篇 |
2009年 | 9篇 |
2008年 | 26篇 |
2007年 | 23篇 |
2006年 | 14篇 |
2005年 | 28篇 |
2004年 | 17篇 |
2003年 | 17篇 |
2002年 | 25篇 |
2001年 | 12篇 |
2000年 | 15篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1996年 | 5篇 |
1995年 | 9篇 |
1993年 | 16篇 |
1992年 | 17篇 |
1991年 | 17篇 |
1990年 | 21篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 20篇 |
1984年 | 6篇 |
1982年 | 9篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1979年 | 8篇 |
1978年 | 12篇 |
1977年 | 10篇 |
1976年 | 11篇 |
1975年 | 5篇 |
1974年 | 9篇 |
1973年 | 6篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1968年 | 3篇 |
1967年 | 3篇 |
1966年 | 3篇 |
1965年 | 3篇 |
排序方式: 共有637条查询结果,搜索用时 46 毫秒
111.
Archive for Rational Mechanics and Analysis - In order to accommodate general initial data, an appropriately relaxed notion of renormalized Lagrangian solutions for the Semi-Geostrophic system in... 相似文献
112.
A. A. Zezin V. I. Feldman A. V. Dudnikov S. B. Zezin S. S. Abramchuk S. I. Belopushkin 《High Energy Chemistry》2009,43(2):100-104
The specifics of X-ray-induced reduction of copper(II) ions in the polyacrylic acid-polyethyleneimine-copper(II) (PAA-PEI-Cu2+) complexes were studied. It was found that the action of radiation led to the effective reduction of Cu2+ in the PAA-PEI-Cu2+ films swollen in an aqueous-alcohol medium. The formation of metal nanoparticles in irradiated samples was revealed by electron microscopy and X-ray diffraction techniques. Analysis of ESR data has demonstrated that the Cu2+ reduction rate increases with an increase in the initial concentration of copper ions in the samples. Formal yields of the radiation-chemical reduction of Cu2+ in the PAA-PEI complex films were found to be quite high (>100 ions per100 eV of energy absorbed by the swollen film), which can be explained by involvement of the radiolysis products of aqueous alcoholic solutions (outer medium) in the reduction processes. 相似文献
113.
The shock reflection problem is one of the most important problems in mathematical fluid dynamics, since this problem not
only arises in many important physical situations but also is fundamental for the mathematical theory of multidimensional
conservation laws that is still largely incomplete. However, most of the fundamental issues for shock reflection have not
been understood, including the regularity and transition of different patterns of shock reflection configurations. Therefore,
it is important to establish the regularity of solutions to shock reflection in order to understand fully the phenomena of
shock reflection. On the other hand, for a regular reflection configuration, the potential flow governs the exact behavior
of the solution in C
1,1 across the pseudo-sonic circle even starting from the full Euler flow, that is, both of the nonlinear systems are actually
the same in a physically significant region near the pseudo-sonic circle; thus, it becomes essential to understand the optimal
regularity of solutions for the potential flow across the pseudo-sonic circle (the transonic boundary from the elliptic to
hyperbolic region) and at the point where the pseudo-sonic circle (the degenerate elliptic curve) meets the reflected shock
(a free boundary connecting the elliptic to hyperbolic region). In this paper, we study the regularity of solutions to regular
shock reflection for potential flow. In particular, we prove that the C
1,1-regularity is optimal for the solution across the pseudo-sonic circle and at the point where the pseudo-sonic circle meets the reflected shock.
We also obtain the C
2,α regularity of the solution up to the pseudo-sonic circle in the pseudo-subsonic region. The problem involves two types of
transonic flow: one is a continuous transition through the pseudo-sonic circle from the pseudo-supersonic region to the pseudo-subsonic
region; the other a jump transition through the transonic shock as a free boundary from another pseudo-supersonic region to
the pseudo-subsonic region. The techniques and ideas developed in this paper will be useful to other regularity problems for
nonlinear degenerate equations involving similar difficulties. 相似文献
114.
Behrends R Fuchs K Kaatze U Hayashi Y Feldman Y 《The Journal of chemical physics》2006,124(14):144512
At six temperatures T between 10 and 50 degrees C and at mole fractions x(g) of glycerol (0相似文献
115.
Dorel Feldman 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(10):651-658
This paper reviews recent studies done in academia or industrial laboratories on polymer nanocomposites based on various type of polyolefins like homopolymers, copolymers and polyblends reinforced with various mineral (montmorillonite, bentonite, closite, laponite, layered double hydroxide, etc.) carbon based (graphite, carbon nanotubes, carbon nanofibers, exfoliated graphite, graphene, carbon black, etc.) nanofillers. The review covers their preparation, their mechanical, thermal, flammability, gas barrier capability, electrical, dielectrical, antibacterial characteristics and their potential applications like low weight structural materials, part of optical devices, thermal interface materials, electric and electromagnetic components, absorption, antibacterial materials, etc. 相似文献
116.
We investigate a model for contact angle motion of quasi-static capillary drops resting on a horizontal plane. We prove global in time existence and long time behavior (convergence to equilibrium) in a class of star-shaped initial data for which we show that topological changes of drops can be ruled out for all times. Our result applies to any drop which is initially star-shaped with respect to a small ball inside the drop, given that the volume of the drop is sufficiently large. For the analysis, we combine geometric arguments based on the moving-plane type method with energy dissipation methods based on the formal gradient flow structure of the problem. 相似文献
117.
The pentacyclic alkaloid (±)-meloscine was prepared in 19 steps through a reaction sequence that features a putative azatrimethylenemethane intermediate, generated through cascade cyclization of an allenyl azide substrate, to deliver the core azabicyclo[3.3.0]octadiene substructure. Subsequent manipulation of the peripheral functionality then delivered (±)-meloscine. 相似文献
118.
Feldman D Nagao R Bánsági T Epstein IR Dolnik M 《Physical chemistry chemical physics : PCCP》2012,14(18):6577-6583
We use the photosensitive chlorine dioxide-iodine-malonic acid reaction-diffusion system to study wavenumber locking of Turing patterns to two-dimensional "square" spatial forcing, implemented as orthogonal sets of bright bands projected onto the reaction medium. Various resonant structures emerge in a broad range of forcing wavelengths and amplitudes, including square lattices and superlattices, one-dimensional stripe patterns and oblique rectangular patterns. Numerical simulations using a model that incorporates additive two-dimensional spatially periodic forcing reproduce well the experimental observations. 相似文献
119.
120.
Levine I Weber SM Feldman Y Bendikov T Cohen H Cahen D Vilan A 《Langmuir : the ACS journal of surfaces and colloids》2012,28(1):404-415
A combined electronic transport-structure characterization of self-assembled monolayers (MLs) of alkyl-phosphonate (AP) chains on Al-AlOx substrates indicates a strong molecular structural effect on charge transport. On the basis of X-ray reflectivity, XPS, and FTIR data, we conclude that "long" APs (C14 and C16) form much denser MLs than do "short" APs (C8, C10, C12). While current through all junctions showed a tunneling-like exponential length-attenuation, junctions with sparsely packed "short" AP MLs attenuate the current relatively more efficiently than those with densely packed, "long" ones. Furthermore, "long" AP ML junctions showed strong bias variation of the length decay coefficient, β, while for "short" AP ML junctions β is nearly independent of bias. Therefore, even for these simple molecular systems made up of what are considered to be inert molecules, the tunneling distance cannot be varied independently of other electrical properties, as is commonly assumed. 相似文献