全文获取类型
收费全文 | 935篇 |
免费 | 115篇 |
国内免费 | 31篇 |
专业分类
化学 | 402篇 |
晶体学 | 2篇 |
力学 | 26篇 |
综合类 | 41篇 |
数学 | 525篇 |
物理学 | 85篇 |
出版年
2024年 | 1篇 |
2023年 | 10篇 |
2022年 | 20篇 |
2021年 | 28篇 |
2020年 | 34篇 |
2019年 | 33篇 |
2018年 | 23篇 |
2017年 | 36篇 |
2016年 | 47篇 |
2015年 | 26篇 |
2014年 | 59篇 |
2013年 | 89篇 |
2012年 | 49篇 |
2011年 | 55篇 |
2010年 | 54篇 |
2009年 | 64篇 |
2008年 | 36篇 |
2007年 | 49篇 |
2006年 | 43篇 |
2005年 | 40篇 |
2004年 | 35篇 |
2003年 | 29篇 |
2002年 | 23篇 |
2001年 | 29篇 |
2000年 | 14篇 |
1999年 | 22篇 |
1998年 | 15篇 |
1997年 | 12篇 |
1996年 | 19篇 |
1995年 | 1篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1982年 | 7篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1081条查询结果,搜索用时 15 毫秒
81.
S.Z. Németh 《Applied mathematics and computation》2010,217(5):2184-2190
The notion of exceptional family of elements for general order complementarity problems in Banach spaces will be introduced. It will be shown that for general order complementarity problems defined by completely continuous fields the problem has either a solution or an exceptional family of elements. Finite dimensional examples and an application to integral operators will be given. 相似文献
82.
A.S. Bonnet-Ben Dhia J.F. Mercier S. Pernet 《Journal of Computational and Applied Mathematics》2010,234(6):1868-1875
This paper concerns the finite element simulation of the diffraction of a time-harmonic acoustic wave in the presence of an arbitrary mean flow. Considering the equation for the perturbation of displacement (due to Galbrun), we derive a low-Mach number formulation of the problem which is proved to be of Fredholm type and is therefore well suited for discretization by classical Lagrange finite elements. Numerical experiments are done in the case of a potential flow for which an exact approach is available, and a good agreement is observed. 相似文献
83.
We discuss tournaments in terms of their efficiency as probabilistic mechanisms that select high-quality alternatives (“players”) in a noisy environment. We characterize the selection efficiency of three such mechanisms – contests, binary elimination tournaments, and round-robin tournaments – depending on the shape of the distribution of players’ quality, the number of players, and noise level. The results have implications as to how, and under what circumstances, the efficiency of tournament-based selection can be manipulated. 相似文献
84.
所谓的Rice’s方法是估计交错和Df_n=sum from k=0 to n(_k~n)(-1)~kf_k,其中,序列f_n能扩充为一个解析函数f(n).在算法分析的许多问题中,经常导出序列Df_n.在60年代,Knuth在分类交换基 相似文献
85.
An effective ant colony optimization algorithm (ACO) for multi-objective resource allocation problem (MORAP) 总被引:3,自引:0,他引:3
The multi-objective resource allocation problem (MORAP) addresses the important issue which seeks to find the expected objectives by allocating the limited amount of resource to various activates. Resources may be manpower, assets, raw material or anything else in limited supply which can be used to accomplish the goals. The goals may be objectives (i.e., minimizing costs, or maximizing efficiency) usually driven by specific future needs. In this paper, in order to obtain a set of Pareto solution efficiently, we proposed a modified version of ant colony optimization (ACO), in this algorithm we try to increase the efficiency of algorithm by increasing the learning of ants. Effectiveness and efficiency of proposed algorithm was validated by comparing the result of ACO with hybrid genetic algorithm (hGA) which was applied to MORAP later. 相似文献
86.
We consider two-stage tandem queueing systems attended by two specialized and one flexible server, where all servers have time varying rates. Assuming exponential processing times and linear holding costs, we derive properties of server allocation policies that minimize expected costs over an infinite time horizon. 相似文献
87.
Positive solutions of Neumann problems with singularities 总被引:1,自引:0,他引:1
In this paper, we study the existence of positive solutions to second order singular equations with Neumann boundary conditions. The proof of the main result relies on a nonlinear alternative principle of Leray-Schauder, together with a truncation technique. 相似文献
88.
We prove a Fredholm alternative theorem for a class of asymptotically hyperbolic linear differential difference equations of mixed type. We also establish the cocycle property and the spectral flow property for such equations, providing an effective means of calculating the Fredholm index. Such systems can arise from equations which describe traveling waves in a spatial lattice. 相似文献
89.
90.
Lucas Montero De Espinosa Juan C. Ronda Marina Galià Virginia Cádiz Michael A.R. Meier 《Journal of polymer science. Part A, Polymer chemistry》2009,47(21):5760-5771
The acyclic diene metathesis (ADMET) polymerization of a phosphorus‐containing α,ω‐diene prepared from a plant oil derived building block is reported. Different ruthenium based metathesis catalysts and conditions were tested to optimize the ADMET polymerization of this monomer. Undecylenyl undecenoate was used as fully renewable comonomer to obtain polyesters with different phosphorus contents and to increase the renewable content of the final polymers. Copolymerization caused marked variations in the molecular weights leading to polyesters from 6 to 38 KDa. The effect of the ADMET polymerization temperature in the thermal properties of the copolymers was studied and their thermal degradation and flame retardant properties were evaluated. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5760–5771, 2009 相似文献