全文获取类型
收费全文 | 361篇 |
免费 | 73篇 |
国内免费 | 11篇 |
专业分类
化学 | 70篇 |
力学 | 106篇 |
综合类 | 4篇 |
数学 | 115篇 |
物理学 | 150篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 32篇 |
2020年 | 19篇 |
2019年 | 7篇 |
2018年 | 13篇 |
2017年 | 20篇 |
2016年 | 22篇 |
2015年 | 23篇 |
2014年 | 30篇 |
2013年 | 36篇 |
2012年 | 28篇 |
2011年 | 33篇 |
2010年 | 18篇 |
2009年 | 24篇 |
2008年 | 19篇 |
2007年 | 12篇 |
2006年 | 15篇 |
2005年 | 16篇 |
2004年 | 11篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有445条查询结果,搜索用时 15 毫秒
61.
本文讨论了周期结构复合材料特征值的多尺度计算,提出了高阶多尺度Rayleigh商校正算法,并给出了收敛性分析. 最后,通过大量数值实验结果表明,新算法是有效且必要的. 相似文献
62.
Using multiscale analysis and methods of statistical physics, we show that a solution to the N-atom Liouville equation can be decomposed via an expansion in terms of a smallness parameter , wherein the long scale time behavior depends upon a reduced probability density that is a function of slow-evolving order parameters. This reduced probability density is shown to satisfy the Smoluchowski equation up to O(2) for a given range of initial conditions. Furthermore, under the additional assumption that the nanoparticle momentum evolves on a slow time scale, we show that this reduced probability density satisfies a Fokker–Planck equation up to O(2). This approach has applications to a broad range of problems in the nanosciences. 相似文献
63.
64.
In the recent decade, the meshless methods have been handled for solving most of PDEs due to easiness of the meshless methods. One of the popular meshless methods is the element-free Galerkin (EFG) method that was first proposed for solving some problems in the solid mechanics. The test and trial functions of the EFG are based on the special basis. Recently, some modifications have been developed to improve the EFG method. One of these improvements is the variational multiscale EFG procedure. In the current article, the shape functions of interpolation moving least squares approximation have been applied to the variational multiscale EFG technique for solving the incompressible magnetohydrodynamics flow. In order to reduce the elapsed CPU time of simulation, we employ a reduced-order model based on the proper orthogonal decomposition technique. The current combination can be referred to as the reduced-order variational multiscale EFG technique. To illustrate the reduction in CPU time used as well as the efficiency of the proposed method, we applied it for the two-dimensional cases. 相似文献
65.
Marie-Claude Viallon 《国际流体数值方法杂志》2020,92(5):391-421
The heat equation is solved by using a finite volume discretization in a domain that consists of a two-dimensional central node and several one-dimensional outgoing branches. Several interface connection options to match the submodels set on the node and on the branches, with or without continuity, are looked at. For each of them, a monolithic scheme is defined, and existence and uniqueness of the solution is proved. New schemes are deduced, which are obtained through domain decomposition methods in the form of interface systems, with one or two unknowns per interface. A comparative systematic study is carried out from an algebraic and numerical point of view according to the interface conditions: Dirichlet, Neumann, or Robin. An efficient diagonal preconditioning is proposed. 相似文献
66.
Modes obtained using the Proper Orthogonal Decomposition are used as boundary enrichment functions within a variational multiscale method for the stochastically forced Burgers equation. Initially, large increases in accuracy are obtained using the enrichment functions without stabilisation terms. Then, optimal coefficients for the stabilisation parameter τ of the unresolved scale model are calibrated using a goal‐oriented model‐constrained optimisation technique, resulting in further improvements. As both the determination of the enrichment functions and the optimisation of the coefficients requires high‐accuracy reference data, a scaling procedure is introduced to allow their use over range of conditions. Numerical experiments confirm that the scaling procedure is effective. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
67.
Zongyang Qiu Prof. Li Song Prof. Jin Zhao Prof. Zhenyu Li Prof. Jinlong Yang 《Angewandte Chemie (International ed. in English)》2016,55(34):9918-9921
Metal‐nanoparticle‐catalyzed cutting is a promising way to produce graphene nanostructures with smooth and well‐aligned edges. Using a multiscale simulation approach, we unambiguously identified a “Pac‐Man” cutting mechanism, characterized by the metal nanoparticle “biting off” edge carbon atoms through a synergetic effect of multiple metal atoms. By comparing the reaction rates at different types of edge sites, we found that etching of an entire edge carbon row could be triggered by a single zigzag‐site etching event, which explains the puzzling linear dependence of the overall carbon‐atom etching rate on the nanoparticle surface area observed experimentally. With incorporation of the nanoparticle size effect, the mechanisms revealed herein open a new avenue to improve controllability in graphene cutting. 相似文献
68.
In this paper, we consider second order elliptic problems with rapidly oscillating coefficients. On basis of [O.A. Oleinik, A.S. Shamaev, G.A. Yosifian, Mathematical Problems in Elasticity and Homogenization, North-Holland, Amsterdam, 1992; Wen-ming He, Jun-zhi Cui, A pointwise estimate on the 1-order approximation of , IMA J. Appl. Math. 70 (2005) 241-269] we propose a new approximate method to solve these problems. Of course, we present its error estimate. 相似文献
69.
Adaptive frame methods for elliptic operator equations: the steepest descent approach 总被引:2,自引:0,他引:2
Dahlke Stephan; Raasch Thorsten; Werner Manuel; Fornasier Massimo; Stevenson Rob 《IMA Journal of Numerical Analysis》2007,27(4):717-740
70.
A multiscale network model is presented to model unsaturated moisture transfer in hygroscopic capillary-porous materials showing a broad pore-size distribution. Both capillary effects and water sorption phenomena, water vapour and liquid water transfer are considered. The multiscale approach is based on the concept of examining the porous space at different levels of magnification. The conservation of the water vapour permeability of dry material is used as scaling criterion to link the different pore scales. A macroscopic permeability is deduced from the permeabilities calculated at the different levels of magnification. Each level of magnification is modelled using an isotropic nonplanar 2D cross-squared network. The multiscale network simulates the enhancement of water vapour permeability due to capillary condensation, the hysteresis phenomenon between wetting and drying, and the steep increase of moisture permeability at the critical moisture saturation level. The calculated network permeabilities are compared with experimental data for calcium silicate and ceramic brick and a good agreement is observed. 相似文献