全文获取类型
收费全文 | 12931篇 |
免费 | 437篇 |
国内免费 | 48篇 |
专业分类
化学 | 8909篇 |
晶体学 | 57篇 |
力学 | 423篇 |
数学 | 1718篇 |
物理学 | 2309篇 |
出版年
2023年 | 91篇 |
2022年 | 115篇 |
2021年 | 181篇 |
2020年 | 199篇 |
2019年 | 228篇 |
2018年 | 194篇 |
2017年 | 151篇 |
2016年 | 336篇 |
2015年 | 342篇 |
2014年 | 365篇 |
2013年 | 702篇 |
2012年 | 864篇 |
2011年 | 890篇 |
2010年 | 537篇 |
2009年 | 416篇 |
2008年 | 825篇 |
2007年 | 788篇 |
2006年 | 728篇 |
2005年 | 677篇 |
2004年 | 632篇 |
2003年 | 570篇 |
2002年 | 458篇 |
2001年 | 221篇 |
2000年 | 228篇 |
1999年 | 132篇 |
1998年 | 153篇 |
1997年 | 130篇 |
1996年 | 169篇 |
1995年 | 97篇 |
1994年 | 97篇 |
1993年 | 91篇 |
1992年 | 92篇 |
1991年 | 67篇 |
1990年 | 77篇 |
1989年 | 61篇 |
1988年 | 65篇 |
1986年 | 54篇 |
1985年 | 83篇 |
1984年 | 106篇 |
1983年 | 67篇 |
1982年 | 79篇 |
1981年 | 82篇 |
1980年 | 88篇 |
1979年 | 65篇 |
1978年 | 79篇 |
1977年 | 83篇 |
1976年 | 89篇 |
1975年 | 66篇 |
1974年 | 43篇 |
1973年 | 50篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Mathilde Kammerer-Colin de Verdière 《Comptes Rendus Mathematique》2004,339(9):625-629
For generic families of vector fields or transformations, normally hyperbolic invariant products of spheres appear near partially elliptic rest points. To cite this article: M. Kammerer-Colin de Verdière, C. R. Acad. Sci. Paris, Ser. I 339 (2004). 相似文献
52.
Pierre Crispel Pierre Degond Céline Parzani Marie-Hélène Vignal 《Comptes Rendus Mathematique》2004,338(4):327-332
In this Note, we propose three formulations of a model describing a quasi-neutral plasma with non-vanishing current. In order to study and compare the numerical efficiency of each formulation, two test-problems are implemented in one dimension. The first is a periodic perturbation of a uniform stationary plasma. The second is a case of plasma expansion in vacuum between two electrodes. To cite this article: P. Crispel et al., C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
53.
We prove that given a simply connected compact manifold M and a
closed manifold N, any map in the Sobolev space W
1,2(M,N) can be
approximated weakly by smooth maps between M and N.
Submitted: September 2002, Final version: November 2002. 相似文献
54.
Whereas glucose oxidase and related proteins are encapsulated readily in silica sol–gels, α-hydroxy enzymes such as lactate
oxidase (LOx), are reported to be damaged by electrostatic interaction with these matrices. Based on a previous report, poly(ethyleneimine),
PEI, was evaluated as a protecting compound under conditions suited to analytical measurements. With LOx and PEI co-encapsulated
in a silica sol–gel, the enzyme retained 62% of its initial activity after 20 days. In the absence of PEI, activity was lost
during the processing. Batch analytical measurements with enzyme-doped sol–gel yielded a linear response over the range 0.5–2.0 mM
lactate and a detection limit of 0.03 mM lactate. Both simple incorporation of LOx in a silica sol–gel and an alternative
protection method, blocking the ion-exchange sites on silica with La(III), failed. These negative results supported the hypothesis
that the efficacy of PEI was related to its formation of a protective sheath around the enzyme.
Author for correspondence. E-mail: coxja@muohio.edu
Received July 29, 2002; accepted December 15, 2002
Published online May 19, 2003 相似文献
55.
Patrick Lacoste 《Comptes Rendus Mathematique》2004,339(10):727-732
. We present practical means to obtain a positive diagonal matrix for the first order Raviart–Thomas–Nédélec finite elements. Applying it to the second order Maxwell equations allows us to use explicit time schemes to solve the resulting differential system. To cite this article: P. Lacoste, C. R. Acad. Sci. Paris, Ser. I 339 (2004). 相似文献
56.
Patrick Ingram 《Journal of Number Theory》2007,123(2):473-486
Let n?5 be an integer. We provide an effective method for finding all elliptic curves in short Weierstrass form E/Q with j(E)∈{0,1728} and all P∈E(Q) such that the nth term in the elliptic divisibility sequence defined by P over E fails to have a primitive divisor. In particular, we improve recent results of Everest, Mclaren, and Ward on the Zsigmondy bounds of elliptic divisibility sequences associated with congruent number curves. 相似文献
57.
Pavol Brunovsky Geneviève Raugel 《Journal of Dynamics and Differential Equations》2003,15(2-3):571-658
We prove that for damped hyperbolic equations the Morse-Smale property (hyperbolicity of equilibria and transversal intersection of stable and unstable manifolds) is generic. More precisely, we prove that in an appropriate functional space of nonlinear terms in the equation, the set of functions for which the latter has the Morse-Smale property is residual, i.e., it is a countable intersection of open dense sets. The result extends a similar result proved in [1] for reaction diffusion equations. However, because of the absence of knowledge about nodal sets of polutions new ideas were needed in the proof. 相似文献
58.
We consider toy cosmological models in which a classical, homogeneous, spinor field provides a dominant or sub-dominant contribution to the energy-momentum tensor of a flat Friedmann-Robertson-Walker universe. We find that, if such a field were to exist, appropriate choices of the spinor self-interaction would generate a rich variety of behaviors, quite different from their widely studied scalar field counterparts. We first discuss solutions that incorporate a stage of cosmic inflation and estimate the primordial spectrum of density perturbations seeded during such a stage. Inflation driven by a spinor field turns out to be unappealing as it leads to a blue spectrum of perturbations and requires considerable fine-tuning of parameters. We next find that, for simple, quartic spinor self-interactions, non-singular cyclic cosmologies exist with reasonable parameter choices. These solutions might eventually be incorporated into a successful past- and future-eternal cosmological model free of singularities. In an Appendix, we discuss the classical treatment of spinors and argue that certain quantum systems might be approximated in terms of such fields. 相似文献
59.
Michèle Audin 《manuscripta mathematica》2007,124(4):533-550
In this paper, we investigate symplectic manifolds endowed with a Morse–Bott function with only two critical submanifolds,
one of which is Lagrangian while the other one is symplectic. 相似文献
60.
Details are given of a new method allowing an exact calculation of the spontaneous magnetization in the corner as well as along the edge at an arbitrary distance of the corner for a rectangular planar Ising ferromagnet. 相似文献