全文获取类型
收费全文 | 284篇 |
免费 | 10篇 |
国内免费 | 3篇 |
专业分类
化学 | 8篇 |
力学 | 13篇 |
数学 | 213篇 |
物理学 | 18篇 |
综合类 | 45篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 5篇 |
2013年 | 17篇 |
2012年 | 17篇 |
2011年 | 18篇 |
2010年 | 13篇 |
2009年 | 25篇 |
2008年 | 33篇 |
2007年 | 20篇 |
2006年 | 10篇 |
2005年 | 13篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有297条查询结果,搜索用时 15 毫秒
61.
屈爱芳 《数学年刊A辑(中文版)》2011,32(2):245-256
描述理想的低温等离子体中电磁波传播的模型是一个椭圆双曲混合型方程.证明了该方程闭Dirichlet问题弱解的存在唯一性.该结果关于区域的几何结构要求较少.由于这里所讨论的方程的奇异性与Keldysh方程的奇异性有相似性质,而后者的奇异性比Tricomi方程更强,因此关于其正则性的研究是很有意义的.作者给出了一个内正则性结果. 相似文献
62.
63.
We consider uniform stability to a nontrivial equilibrium of a nonlinear fluid–structure interaction (FSI) defined on a two or three dimensional bounded domain. Stabilization is achieved via boundary and/or interior feedback controls implemented on both the fluid and the structure. The interior damping on the fluid combining with the viscosity effect stabilizes the dynamics of fluid. However, this dissipation propagated from the fluid alone is not sufficient to drive uniformly to equilibrium the entire coupled system. Therefore, additional interior damping on the wave component or boundary porous like damping on the interface is considered. A geometric condition on the interface is needed if only boundary damping on the wave is active. The main technical difficulty is the mismatch of regularity of hyperbolic and parabolic component of the coupled system. This is overcome by considering special multipliers constructed from Stokes solvers. The uniform stabilization result obtained in this article is global for the fully coupled FSI model. 相似文献
64.
In this article we present an inversion algorithm for the determination of the shape of a two-dimensional penetrable obstacle from knowledge of the elastic field generated by an incident plane compressional and shear wave. In particular, Kirsch's improved variant of the linear sampling method, the so called (F * F?)1/4-method is extended to the elastic case. A mathematical analysis that reveals the compactness and normality of the far-field operator is presented. Finally, numerical results are presented showing the robustness of the (F * F?)1/4-method with respect to noise. 相似文献
65.
Dennis Kriventsov 《偏微分方程通讯》2013,38(12):2081-2106
We prove a C 1, α interior regularity theorem for fully nonlinear uniformly elliptic integro-differential equations without assuming any regularity of the kernel. We then give some applications to linear theory and higher regularity of a special class of nonlinear operators. 相似文献
66.
设珮犠(狋):犚犖+ →犚犱是犖指标犱维广义Wiener过程,对任意紧集犈1,…,犈犿犚犖> ,该文研究了犿项代数和珮犠(犈1)…珮犠(犈犿)的Hausdorff维数,Packing维数和正的Lebesgue测度及内点的存在性. 其结果包含并推广了布朗单的结果. 相似文献
67.
Support-graph preconditioners have been shown to be a valuable tool for the iterative solution, via a Preconditioned Conjugate
Gradient method, of the KKT systems that must be solved at each iteration of an Interior Point algorithm for the solution
of Min Cost Flow problems. These preconditioners extract a proper triangulated subgraph, with “large” weight, of the original
graph: in practice, trees and Brother-Connected Trees (BCTs) of depth two have been shown to be the most computationally efficient
families of subgraphs. In the literature, approximate versions of the Kruskal algorithm for maximum-weight spanning trees
have most often been used for choosing the subgraphs; Prim-based approaches have been used for trees, but no comparison have
ever been reported. We propose Prim-based heuristics for BCTs, which require nontrivial modifications w.r.t. the previously
proposed Kruskal-based approaches, and present a computational comparison of the different approaches, which shows that Prim-based
heuristics are most often preferable to Kruskal-based ones.
This paper has been partially supported by the UE Marie Curie Research Training Network no. 504438 ADONET. 相似文献
68.
通过实验性胆道梗阻及胆肠内引流实验观察梗阻后门脉压力逐渐增加,肝小叶中央静脉和肝窦周围组织胶原纤维沉积渐增,小叶中央静脉变窄、肝窦阻塞,早期行胆肠内引流可减轻上述症状. 相似文献
69.
In this study, we show that the axisymmetric Levinson plate theory is exclusively an interior theory and we provide a consistent variational formulation for it. First, we discuss an annular Levinson plate according to a vectorial formulation. The boundary layer of the plate is not modeled and, thus, the interior stresses acting as surface tractions do work on the lateral edges of the plate. This feature is confirmed energetically by the Clapeyron's theorem. The variational formulation is carried out for the annular Levinson plate by employing the principle of virtual displacements. As a novel contribution, the formulation includes the external virtual work done by the tractions based on the interior stresses on the inner and outer lateral edges of the Levinson plate. The obtained plate equations are consistent with the vectorially derived Levinson equations. Finally, we develop an exact plate finite element both by a force-based method and from the total potential energy of the Levinson plate. 相似文献
70.
The remarkable properties of graphene, including unusually high mechanical strength and stiffness, have been well-documented. In this paper, we combine an analytical solution for ballistic impact into a thin isotropic membrane, with ab initio density functional theory calculations for graphene under uniaxial tension, to predict the penetration resistance of multi-layer graphene membranes. The calculations show that continuous graphene membranes could enable ballistic barriers of extraordinary performance, enabling resistance to penetration at masses up to 100× lighter than existing state-of-the-art barrier materials. The very high elastic wave speed and strain energy to failure are the major drivers of this increase in performance. However, the in-plane mechanical isotropy of graphene, as compared to conventional orthotropic woven textiles, also contributes significantly to the efficiency of graphene as a barrier material. This result suggests that, for barrier applications, isotropic membranes composed of covalently bonded two-dimensional molecular networks could provide distinct advantages over fiber-based textiles derived from linear polymers. 相似文献