全文获取类型
收费全文 | 57874篇 |
免费 | 1869篇 |
国内免费 | 116篇 |
专业分类
化学 | 35559篇 |
晶体学 | 304篇 |
力学 | 1027篇 |
综合类 | 3篇 |
数学 | 11156篇 |
物理学 | 11810篇 |
出版年
2023年 | 397篇 |
2022年 | 432篇 |
2021年 | 761篇 |
2020年 | 876篇 |
2019年 | 819篇 |
2018年 | 1466篇 |
2017年 | 1203篇 |
2016年 | 2037篇 |
2015年 | 1664篇 |
2014年 | 1676篇 |
2013年 | 3603篇 |
2012年 | 3458篇 |
2011年 | 3411篇 |
2010年 | 2262篇 |
2009年 | 1969篇 |
2008年 | 2986篇 |
2007年 | 2800篇 |
2006年 | 2536篇 |
2005年 | 2530篇 |
2004年 | 2125篇 |
2003年 | 1804篇 |
2002年 | 1560篇 |
2001年 | 1160篇 |
2000年 | 1197篇 |
1999年 | 833篇 |
1998年 | 637篇 |
1997年 | 566篇 |
1996年 | 724篇 |
1995年 | 502篇 |
1994年 | 603篇 |
1993年 | 528篇 |
1992年 | 555篇 |
1991年 | 471篇 |
1990年 | 525篇 |
1989年 | 435篇 |
1988年 | 424篇 |
1987年 | 377篇 |
1986年 | 381篇 |
1985年 | 523篇 |
1984年 | 499篇 |
1983年 | 383篇 |
1982年 | 402篇 |
1981年 | 406篇 |
1980年 | 335篇 |
1979年 | 314篇 |
1978年 | 329篇 |
1977年 | 307篇 |
1976年 | 323篇 |
1975年 | 275篇 |
1973年 | 292篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
151.
152.
Tomás Chacón Rebollo Antonio Domı́nguez Delgado Enrique D. Fernández Nieto 《Comptes Rendus Mathematique》2004,338(1):85-90
In this work we introduce a class of balanced numerical schemes, up to second order, for the solution of general non-homogeneous hyperbolic systems of conservation laws. We give a general technique to build such schemes. We also prove that they balance up to second order a large class of steady solutions in the whole domain but some subset whose measure tends to zero as the grid size decreases to zero. We finally present an application to Shallow Water equations that exhibit the good performances of some of the schemes introduced. To cite this article: T. Chacón Rebollo et al., C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
153.
In bricklayers' model, which is a generalization of the misanthrope processes, we show that a nontrivial class of product distributions is closed under the time-evolution of the process. This class also includes measures fitting to shock data of the limiting PDE. In particular, we show that shocks of this type with discontinuity of size one perform ordinary nearest neighbor random walks only interacting, in an attractive way, via their jump rates. Our results are related to those of Belitsky and Schütz(4) on the simple exclusion process, although we do not use quantum formalism as they do. The structures we find are described from a fixed position. Similar ones were found in Balázs,(2) valak as seen from the random position of the second class particle. 相似文献
154.
155.
The rate-dependent effects in metallic ferromagnetic materials with magnetization processes attributed to domain-walls motion were studied. The experimental method for eddy-current relaxation time determination was proposed. Some discrepancies between the data and theoretical predictions were observed and discussed. The origin of these discrepancies is accounted for by the decrease of viscous-type relaxation process as the rate of change of averaged magnetization is approaching zero. 相似文献
156.
Sylvia Pulmannová 《International Journal of Theoretical Physics》2003,42(5):907-919
Tensor products of quantum logics and effect algebras with some known problems are reviewed. It is noticed that although tensor products of effect algebras having at least one state exist, in the category of complex Hilbert space effect algebras similar problems as with tensor products of projection lattices occur. Nevertheless, if one of the two coupled physical systems is classical, tensor product exists and can be considered as a Boolean power. Some applications of tensor products (in the form of Boolean powers) to quantum measurements are reviewed. 相似文献
157.
We show that every plane graph of diameter 2r in which all inner faces are triangles and all inner vertices have degree larger than 5 can be covered with two balls of radius r. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 65–80, 2003 相似文献
158.
We have used the periodic quantum-mechanical method with density functional theory at the B3LYP level in order to study TiO2/Sn doped (1 1 0) surfaces and have investigated the structural, electronic and energy band properties of these oxides. Our calculated relaxation directions for TiO2 is the experimental one and is also in agreement with other theoretical results. We also observe for the doped systems relaxation of lattice positions of the atoms. Modification of Sn, O and Ti charges depend on the planes and positions of the substituted atoms. Doping can modify the Fermi levels, energy gaps as well as the localization and composition of both valence and conduction band main components. Doping can also modify the chemical, electronic and optical properties of these oxides surfaces increasing their suitability for use as gas sensors and optoelectronic devices. 相似文献
159.
160.
The physico-chemical properties and reactivity tested by hydrogen reduction have been studied for two series of NiO-ZnO mixed oxides of various composition. The solid nickel oxide or zinc oxide in interaction with the solution of nitrate of the second component were used as the precursors in each series. The differences in some physico-chemical parameters of the samples in both series were correlated with their reduction behaviour, followed both in iso- and non-isothermal regime. Moreower, the influence of various factors modifying the reactivity of mixed oxides was also investigated and the results were compared with those obtained from earlier studied analogous systems of quite different origin.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献