全文获取类型
收费全文 | 438篇 |
免费 | 36篇 |
国内免费 | 36篇 |
专业分类
化学 | 50篇 |
力学 | 29篇 |
综合类 | 4篇 |
数学 | 357篇 |
物理学 | 70篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 11篇 |
2017年 | 19篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 19篇 |
2013年 | 52篇 |
2012年 | 13篇 |
2011年 | 18篇 |
2010年 | 17篇 |
2009年 | 16篇 |
2008年 | 25篇 |
2007年 | 29篇 |
2006年 | 23篇 |
2005年 | 18篇 |
2004年 | 20篇 |
2003年 | 19篇 |
2002年 | 24篇 |
2001年 | 16篇 |
2000年 | 13篇 |
1999年 | 17篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 4篇 |
1979年 | 2篇 |
排序方式: 共有510条查询结果,搜索用时 125 毫秒
1.
Jenn‐Long Liu 《国际流体数值方法杂志》2004,44(12):1299-1315
This paper presents a relaxation algorithm, which is based on the overset grid technology, an unsteady three‐dimensional Navier–Stokes flow solver, and an inner‐ and outer‐relaxation method, for simulation of the unsteady flows of moving high‐speed trains. The flow solutions on the overlapped grids can be accurately updated by introducing a grid tracking technique and the inner‐ and outer‐relaxation method. To evaluate the capability and solution accuracy of the present algorithm, the computational static pressure distribution of a single stationary TGV high‐speed train inside a long tunnel is investigated numerically, and is compared with the experimental data from low‐speed wind tunnel test. Further, the unsteady flows of two TGV high‐speed trains passing by each other inside a long tunnel and at the tunnel entrance are simulated. A series of time histories of pressure distributions and aerodynamic loads acting on the train and tunnel surfaces are depicted for detailed discussions. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
2.
单调优化是指目标函数与约束函数均为单调函数的全局优化问题.本文提出一种新的凸化变换方法把单调函数化为凸函数,进而把单调优化问题化为等价的凸极大或凹极小问题,然后采用Hoffman的外逼近方法来求得问题的全局最优解.我们把这种凸化方法同Tuy的Polyblock外逼近方法作了比较,通过数值比较可以看出本文提出的凸化的方法在收敛速度上明显优于Polyblock方法. 相似文献
3.
We prove that there is a first-order sentence ϕ such that the group of all computable automorphisms of the ordering of the
rational numbers is its only model among the groups that are embeddable in the group of all computable permutations.
Supported by a Scheme 2 grant from the London Mathematical Society.
__________
Translated from Algebra i Logika, Vol. 46, No. 5, pp. 649–662, September–October, 2007. 相似文献
4.
We find the existence of a quantum thermal effect, “Hawking absorption.” near the inner horizon of the Kerr–Newman black hole. Redefining the entropy, temperature, angular velocity, and electric potential of the black hole, we give a new formulation of the Bekenstein–Smarr formula. The redefined entropy vanishes for absolute zero temperature of the black hole and hence it is interpreted as the Planck absolute entropy of the KN black hole. 相似文献
5.
6.
在本文中,我们提出了双凹规划问题和更一般的广义凹规划问题。我们给出了双凹规划问题的整体最优性条件,并构造了一个有限终止外逼近算法。 相似文献
7.
Automorphisms of groups acting faithfully on rooted trees are studied. We find conditions under which every automorphism of such a group is induced by a conjugation from the full automorphism group of the rooted tree. These results are applied to known examples such as Grigorchuk groups, Gupta–Sidki group, etc. 相似文献
8.
Peter J. Cameron 《组合设计杂志》2005,13(6):466-470
It is shown that there is a function g on the natural numbers such that a partial Steiner triple system U on u points can be embedded in a Steiner triple system V on ν points, in such a way that all automorphisms of U can be extended to V, for every admissible ν satisfying ν > g(u). We find exponential upper and lower bounds for g. © 2005 Wiley Periodicals, Inc. J Combin Designs. 相似文献
9.
Five non-isomorphic quasi-symmetric 2-(49, 9, 6) designs are known. They arise from extremal self-dual [50, 25, 10] codes with a certain weight enumerator. Four of them have an automorphism of order 3 fixing two points. In this paper, it is shown that there are exactly 48 inequivalent extremal self-dual [50, 25, 10] code with this weight enumerator and an automorphism of order 3 fixing two points. 44 new quasi-symmetric 2-(49, 9, 6) designs with an automorphism of order 3 are constructed from these codes. 相似文献
10.
Convex programs with an additional reverse convex constraint 总被引:2,自引:0,他引:2
H. Tuy 《Journal of Optimization Theory and Applications》1987,52(3):463-486
A method is presented for solving a class of global optimization problems of the form (P): minimizef(x), subject toxD,g(x)0, whereD is a closed convex subset ofR
n
andf,g are convex finite functionsR
n
. Under suitable stability hypotheses, it is shown that a feasible point
is optimal if and only if 0=max{g(x):xD,f(x)f(
)}. On the basis of this optimality criterion, the problem is reduced to a sequence of subproblemsQ
k
,k=1, 2, ..., each of which consists in maximizing the convex functiong(x) over some polyhedronS
k
. The method is similar to the outer approximation method for maximizing a convex function over a compact convex set. 相似文献