全文获取类型
收费全文 | 8673篇 |
免费 | 741篇 |
国内免费 | 1108篇 |
专业分类
化学 | 148篇 |
晶体学 | 2篇 |
力学 | 489篇 |
综合类 | 188篇 |
数学 | 8305篇 |
物理学 | 1390篇 |
出版年
2024年 | 14篇 |
2023年 | 83篇 |
2022年 | 92篇 |
2021年 | 133篇 |
2020年 | 180篇 |
2019年 | 245篇 |
2018年 | 233篇 |
2017年 | 253篇 |
2016年 | 278篇 |
2015年 | 192篇 |
2014年 | 412篇 |
2013年 | 651篇 |
2012年 | 358篇 |
2011年 | 511篇 |
2010年 | 478篇 |
2009年 | 669篇 |
2008年 | 620篇 |
2007年 | 676篇 |
2006年 | 557篇 |
2005年 | 501篇 |
2004年 | 420篇 |
2003年 | 457篇 |
2002年 | 410篇 |
2001年 | 291篇 |
2000年 | 309篇 |
1999年 | 292篇 |
1998年 | 244篇 |
1997年 | 239篇 |
1996年 | 154篇 |
1995年 | 81篇 |
1994年 | 76篇 |
1993年 | 53篇 |
1992年 | 49篇 |
1991年 | 28篇 |
1990年 | 28篇 |
1989年 | 24篇 |
1988年 | 29篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 21篇 |
1984年 | 31篇 |
1983年 | 18篇 |
1982年 | 26篇 |
1981年 | 16篇 |
1980年 | 20篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1936年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
991.
992.
Peng Gao 《Journal of Differential Equations》2019,266(10):6702-6738
The purpose of this paper is to establish Bogoliubov averaging principle of stochastic reaction–diffusion equation with a stochastic process and a small parameter. The solutions to stochastic reaction–diffusion equation can be approximated by solutions to averaged stochastic reaction–diffusion equation in the sense of convergence in probability and in distribution. Namely, we establish a weak law of large numbers for the solution of stochastic reaction–diffusion equation. 相似文献
993.
In this paper, the authors give the local L~2 estimate of the maximal operator S_(φ,γ)~* of the operator family {S_(t,φ,γ)} defined initially by ■which is the solution(when n = 1) of the following dispersive equations(~*) along a curve γ:■where φ : R~+→R satisfies some suitable conditions and φ((-?)~(1/2)) is a pseudo-differential operator with symbol φ(|ξ|). As a consequence of the above result, the authors give the pointwise convergence of the solution(when n = 1) of the equation(~*) along curve γ.Moreover, a global L~2 estimate of the maximal operator S_(φ,γ)~* is also given in this paper. 相似文献
994.
Jordan operator algebras are norm‐closed spaces of operators on a Hilbert space with for all . In two recent papers by the authors and Neal, a theory for these spaces was developed. It was shown there that much of the theory of associative operator algebras, in particular, surprisingly much of the associative theory from several recent papers of the first author and coauthors, generalizes to Jordan operator algebras. In the present paper we complete this task, giving several results which generalize the associative case in these papers, relating to unitizations, real positivity, hereditary subalgebras, and a couple of other topics. We also solve one of the three open problems stated at the end of our earlier joint paper on Jordan operator algebras. 相似文献
995.
996.
997.
998.
We use three different results of the averaging theory of first order for studying the existence of new periodic solutions in the two Duffing differential equations $ddot y+ a sin y= b sin t$ and $ddot y+a y-c y^3=bsin t$, where $a$, $b$ and $c$ are real parameters. 相似文献
999.
The Complete Biorthogonal Expansion Theorem
and Its Application to a Class of Rectangular
Plate Equations 下载免费PDF全文
In this paper, we first establish the separable $Hamiltonian$ system of rectangular cantilever thin plate bending problems by choosing proper dual vectors. Then using the characteristics of off-diagonal infinite-dimensional $Hamiltonian$ operator matrix, we derive the biorthogonal relationships of the eigenfunction systems and based on it we further obtain the complete biorthogonal expansion theorem. Finally, applying this theorem we obtain the general solutions of rectangular cantilever thin plate bending problems with two opposite edges slidingly supported. 相似文献
1000.
In this work we study the existence of new periodic solutions for
the well knwon class of Duffing differential equation of the form
$x^{\prime\prime}+ c x^{\prime}+ a(t) x +b(t) x^3 = h(t)$, where $c$
is a real parameter, $a(t)$, $b(t)$ and $h(t)$ are continuous
$T$--periodic functions. Our results are proved using three
different results on the averaging theory of first order. 相似文献