全文获取类型
收费全文 | 1466篇 |
免费 | 225篇 |
国内免费 | 163篇 |
专业分类
化学 | 565篇 |
晶体学 | 33篇 |
力学 | 67篇 |
综合类 | 12篇 |
数学 | 493篇 |
物理学 | 684篇 |
出版年
2024年 | 2篇 |
2023年 | 25篇 |
2022年 | 57篇 |
2021年 | 72篇 |
2020年 | 67篇 |
2019年 | 56篇 |
2018年 | 58篇 |
2017年 | 72篇 |
2016年 | 73篇 |
2015年 | 60篇 |
2014年 | 75篇 |
2013年 | 131篇 |
2012年 | 77篇 |
2011年 | 72篇 |
2010年 | 65篇 |
2009年 | 78篇 |
2008年 | 100篇 |
2007年 | 75篇 |
2006年 | 85篇 |
2005年 | 41篇 |
2004年 | 37篇 |
2003年 | 36篇 |
2002年 | 52篇 |
2001年 | 45篇 |
2000年 | 45篇 |
1999年 | 39篇 |
1998年 | 44篇 |
1997年 | 26篇 |
1996年 | 28篇 |
1995年 | 14篇 |
1994年 | 19篇 |
1993年 | 9篇 |
1992年 | 15篇 |
1991年 | 13篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 9篇 |
1986年 | 14篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 1篇 |
1982年 | 10篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1854条查询结果,搜索用时 15 毫秒
111.
We establish that an ordered Banach space is order-isomorphic to c0 if and only if it is a -Dedekind complete vector lattice and its norm dual is order-isomorphic to 1. 相似文献
112.
We considered the Heisenberg model on the recursive lattices with multi-spin interaction in a strong magnetic field as an approximation of the two-dimensional kagome lattice, as well as hexagonal recursive lattices as an approximation of triangular lattice, for solid 3He. In a strong magnetic field it is possible to approximate the Heisenberg model with the Izing one. Using dynamic approach, we obtain exact recursion relations for partition functions. Diagrams of the magnetization versus external magnetic field with different spin-exchange parameters and temperatures are presented. Magnetization plateaux, bifurcation points, and doublings are obtained. 相似文献
113.
Zhou Hai-jun 《Frontiers of Physics in China》2007,2(2):238-250
At sufficiently low temperatures, the configurational phase space of a large spin-glass system breaks into many separated
domains, each of which is referred to as a macroscopic state. The system is able to visit all spin configurations of the same
macroscopic state, while it can not spontaneously jump between two different macroscopic states. Ergodicity of the whole configurational
phase space of the system, however, can be recovered if a temperature-annealing process is repeated an infinite number of
times. In a heating-annealing cycle, the environmental temperature is first elevated to a high level and then decreased extremely
slowly until a final low temperature T is reached. Different macroscopic states may be reached in different rounds of the annealing experiment; while the probability
of finding the system in macroscopic state α decreases exponentially with the free energy F
α
(T) of this state. For finite-connectivity spin glass systems, we use this free energy Boltzmann distribution to formulate the
cavity approach of Mézard and Parisi [Eur. Phys. J. B, 2001, 20: 217] in a slightly different form. For the ±J spin-glass model on a random regular graph of degree K = 6, the predictions of the present work agree with earlier simulational and theoretical results.
相似文献
114.
Hierarchical structure in polymer‐based drug delivery systems as probed by calorimetric measurements
Pascale Valot Nathalie Sintes‐Zydowicz Jean‐Marie Nedelec Mohamed Baba 《Journal of Polymer Science.Polymer Physics》2010,48(18):1939-1945
Thermoporosimetry (TPM), a differential scanning calorimetry technique that relies on the shift of transition temperatures caused by the confinement of liquids, was applied to elucidate the complex morphology of drug‐loaded polymeric microcapsules prepared by the emulsion solvent evaporation method. For the very first time, TPM has been applied simultaneously with two liquids as structural probes. It was found that Miglyol, which dissolves the selected drug (Ibuprofen), is confined inside vesicles having a mean radius of 26.3 nm, whereas water, which is the continuous phase, is trapped inside a swollen polymeric network of Eudragit with an average mesh radius of 1.7 nm. A proposed hierarchical structure is given, which predicts that Eudragit microcapsules are formed from a collection of inert oil vesicles partitioned by polymeric Eudragit membranes swollen by water. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1939–1945, 2010 相似文献
115.
116.
Rohallah Tavakoli 《国际流体数值方法杂志》2008,57(12):1753-1770
An efficient and easy to implement method to generate Cartesian grids is presented. The presented method generates various kinds of Cartesian grids such as uniform, octree and embedded boundary grids. It supports the variation of grid size along each spatial direction as well as anisotropic and non‐graded refinements. The efficiency and ease of implementation are the main benefits of the presented method in contrast to the alternative methods. Regarding octree grid generation, applying a simple and efficient data compression method permits to store all grid levels without considerable memory overhead. The presented method generates octree grids up to a 13‐level refinement (81923 grids on the finest level) from a complicated geometry in a few minutes on the traditional desktop computers. The FORTRAN 90 implementation of the presented method is freely available under the terms of the GNU general public license. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
117.
118.
Summary A detailed experimental analysis of the inelastic crosssection along the [111]-direction in Co−Ni alloys is presented. Using
a simple model and studying the cross-section as a function of both composition and temperature, it is shown that interesting
information about the h.c.p.-f.c.c. transition can be gained in these alloys.
Riassunto Nel presente lavoro si describe un’analisi sperimentale dettagliata della sezione d’urto anelastica dei neutroni lungo la direzione [111] in leghe Co−Ni. Impiegando un modello relativamente semplice e studiando la sezione d’urto in funzione di temperatura e concentrazione, si mostra che si possono ottenere utili informazioni riguardanti la transizione h.c.p.-f.c.c.相似文献
119.
120.
Aiming to provide an appropriate number K of clusters, in this paper, we propose a new criterion function - H criterion function, whose three properties have also been proved. We validate the performance of the H criterion function on one artificial dataset and three real-world datasets, and the results are almostly consistent with a previous method. The nonparametric criterion we proposed is intuitive, simple and the computational cost is acceptable. 相似文献