全文获取类型
收费全文 | 11711篇 |
免费 | 40篇 |
国内免费 | 56篇 |
专业分类
化学 | 3776篇 |
晶体学 | 12篇 |
力学 | 99篇 |
综合类 | 7篇 |
数学 | 4263篇 |
物理学 | 3650篇 |
出版年
2024年 | 2篇 |
2023年 | 14篇 |
2022年 | 6篇 |
2021年 | 4篇 |
2020年 | 44篇 |
2019年 | 72篇 |
2018年 | 84篇 |
2017年 | 86篇 |
2016年 | 87篇 |
2015年 | 29篇 |
2014年 | 52篇 |
2013年 | 639篇 |
2012年 | 384篇 |
2011年 | 526篇 |
2010年 | 432篇 |
2009年 | 2815篇 |
2008年 | 2202篇 |
2007年 | 939篇 |
2006年 | 424篇 |
2005年 | 324篇 |
2004年 | 319篇 |
2003年 | 196篇 |
2002年 | 118篇 |
2001年 | 114篇 |
2000年 | 115篇 |
1999年 | 78篇 |
1998年 | 177篇 |
1997年 | 158篇 |
1996年 | 53篇 |
1995年 | 243篇 |
1994年 | 204篇 |
1993年 | 183篇 |
1992年 | 244篇 |
1991年 | 213篇 |
1990年 | 71篇 |
1989年 | 67篇 |
1988年 | 38篇 |
1987年 | 1篇 |
1986年 | 6篇 |
1985年 | 19篇 |
1984年 | 10篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1976年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
931.
We consider L1-solutions of the following refinement type equations
932.
Kijung Lee 《Journal of Mathematical Analysis and Applications》2009,353(1):24-42
We develop an Lp theory for the Cauchy problem of linear partial differential systems of the form
933.
Fei Guo 《Journal of Mathematical Analysis and Applications》2009,353(1):88-98
In this paper, the multiplicity of Lagrangian orbits on C2 smooth compact symmetric star-shaped hypersurfaces with respect to the origin in R2n is studied. These Lagrangian orbits begin from one Lagrangian subspace and end on another. An infinitely many existence result is proved via Z2-index theory. This is a multiplicity result about the Arnold Chord Conjecture in some sense, and is a generalization of the problem about the multiplicity of Lagrangian orbits beginning from and ending on the same Lagrangian subspace which was considered in the authors' previous paper [F. Guo, C. Liu, Multiplicity of Lagrangian orbits on symmetric star-shaped hypersurfaces, Nonlinear Anal. 69 (4) (2008) 1425-1436]. 相似文献
934.
John Michael Rassias 《Journal of Mathematical Analysis and Applications》2009,356(1):302-309
In 1940 S.M. Ulam proposed the famous Ulam stability problem. In 1941 D.H. Hyers solved the well-known Ulam stability problem for additive mappings subject to the Hyers condition on approximately additive mappings. The first author of this paper investigated the Hyers-Ulam stability of Cauchy and Jensen type additive mappings. In this paper we generalize results obtained for Jensen type mappings and establish new theorems about the Hyers-Ulam stability for general additive functional equations in quasi-β-normed spaces. 相似文献
935.
The stability and boundedness of the solution for stochastic functional differential equation with finite delay have been studied by several authors, but there is almost no work on the stability of the solutions for stochastic functional differential equations with infinite delay. The main aim of this paper is to close this gap. We establish criteria of pth moment ψγ(t)-bounded for neutral stochastic functional differential equations with infinite delay and exponentially stable criteria for stochastic functional differential equations with infinite delay, and we also illustrate the result with an example. 相似文献
936.
937.
Chantal Labbé 《Applied mathematics and computation》2009,215(5):1852-1867
Quantities of interest in ruin theory are investigated under the general framework of the expected discounted penalty function, assuming a risk model where both premiums and claims follow compound Poisson processes. Both a defective renewal equation and an integral equation satisfied by the expected discounted penalty function are established. Some implications that these equations have on particular quantities such as the discounted deficit and the probability of ultimate ruin are illustrated. Finally, the case when premiums have Erlang(n,β) distribution and the distribution of the claims is arbitrary is investigated in more depth. Throughout the paper specific examples where claims and premiums have particular distributions are provided. 相似文献
938.
We consider the symmetric schemes in Boundary Value Methods (BVMs) applied to delay differential equations y′(t)=ay(t)+by(t-τ) with real coefficients a and b. If the numerical solution tends to zero whenever the exact solution does, the symmetric scheme with (k1+m,k2)-boundary conditions is called τk1,k2(0)-stable. Three families of symmetric schemes, namely the Extended Trapezoidal Rules of first (ETRs) and second (ETR2s) kind, and the Top Order Methods (TOMs), are considered in this paper.By using the boundary locus technology, the delay-dependent stability region of the symmetric schemes are analyzed and their boundaries are found. Then by using a necessary and sufficient condition, the considered symmetric schemes are proved to be τν,ν-1(0)-stable. 相似文献
939.
Toru Araki 《Discrete Applied Mathematics》2009,157(8):1677-1686
An L(p,q)-labeling of a graph G is an assignment f from vertices of G to the set of non-negative integers {0,1,…,λ} such that |f(u)−f(v)|≥p if u and v are adjacent, and |f(u)−f(v)|≥q if u and v are at distance 2 apart. The minimum value of λ for which G has L(p,q)-labeling is denoted by λp,q(G). The L(p,q)-labeling problem is related to the channel assignment problem for wireless networks.In this paper, we present a polynomial time algorithm for computing L(p,q)-labeling of a bipartite permutation graph G such that the largest label is at most (2p−1)+q(bc(G)−2), where bc(G) is the biclique number of G. Since λp,q(G)≥p+q(bc(G)−2) for any bipartite graph G, the upper bound is at most p−1 far from optimal. 相似文献
940.
We can describe higher-dimensional classical spaces by analytical projective geometry, if we embed the d-dimensional real space onto a d + 1-dimensional real projective metric vector space. This method allows an approach to Euclidean, hyperbolic, spherical and
other geometries uniformly [8].
To visualize d-dimensional solids, it is customary to make axonometric projection of them. In our opinion the central projection gives more
information about these objects, and it contains the axonometric projection as well, if the central figure is an ideal point
or an s-dimensional subspace at infinity. We suggest a general method which can project solids into any picture plane (space) from
any central figure, complementary to the projection plane (space). Opposite to most of the other algorithms in the literature,
our algorithm projects higher-dimensional solids directly into the two-dimensional picture plane (especially into the computer
screen), it does not use the three-dimensional space for intermediate step.
Our algorithm provides a general, so-called lexicographic visibility criterion in Definition and Theorem 3.4, so it determines
an extended visibility of the d-dimensional solids by describing the edge framework of the two-dimensional surface in front of us. In addition we can move
the central figure and the image plane of the projection, so we can simulate the moving position of the observer at fixed
objects on the computer screen (see first our figures in reverse order).
Supported by DAAD 2008 Multimedia Technology for Mathematics and Computer Science Education. 相似文献