全文获取类型
收费全文 | 554篇 |
免费 | 60篇 |
国内免费 | 77篇 |
专业分类
化学 | 5篇 |
力学 | 91篇 |
综合类 | 8篇 |
数学 | 512篇 |
物理学 | 75篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 9篇 |
2021年 | 10篇 |
2020年 | 15篇 |
2019年 | 9篇 |
2018年 | 8篇 |
2017年 | 13篇 |
2016年 | 11篇 |
2015年 | 13篇 |
2014年 | 19篇 |
2013年 | 29篇 |
2012年 | 27篇 |
2011年 | 47篇 |
2010年 | 50篇 |
2009年 | 38篇 |
2008年 | 31篇 |
2007年 | 32篇 |
2006年 | 39篇 |
2005年 | 37篇 |
2004年 | 27篇 |
2003年 | 22篇 |
2002年 | 27篇 |
2001年 | 17篇 |
2000年 | 15篇 |
1999年 | 20篇 |
1998年 | 21篇 |
1997年 | 25篇 |
1996年 | 13篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1982年 | 6篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有691条查询结果,搜索用时 187 毫秒
101.
In this article, we have used the homotopy perturbation method (HPM) to find the travelling wave solutions for some non-linear initial-value problems in the mathematical physics. These problems consist of the Burgers–Fisher equation, the Kuramoto–Sivashinsky equation, the coupled Schordinger KdV equations and the long–short wave resonance equations together with initial conditions. The results of these problems reveal that the HPM is very powerful, effective, convenient and quite accurate to the systems of non-linear equations. It is predicted that this method can be found widely applicable in engineering and physics. 相似文献
102.
In this article, we discuss the analytic solution of the fully developed shock waves. The homotopy perturbation method is used to solve the shock wave equation, which describes the flow of gases. Unlike the various numerical techniques, which are usually valid for short period of time, the solution of the presented equation is analytic for 0 < t < ∞. The results presented converge very rapidly, indicating that the method is reliable and accurate. 相似文献
103.
The fractional derivatives in the sense of Caputo and the homotopy analysis method are used to construct an approximate solution for the nonlinear space-time fractional derivatives Klein-Gordon equation. The numerical results show that the approaches are easy to implement and accurate when applied to the nonlinear space-time fractional derivatives KleinGordon equation. This method introduces a promising tool for solving many space-time fractional partial differential equations. This method is efficient and powerful in solving wide classes of nonlinear evolution fractional order equations. 相似文献
104.
105.
Marco Grandis 《Applied Categorical Structures》1997,5(1):75-97
We study here a notion of simplicial satellites, as a first step towards a characterisation of simplicial derived functors, a problem unsolved since the latter were introduced.The problem comes from the fact that, in contrast with the abelian case, simplicial derived functors do not produce by themselves an exact sequence. Our solution consists in extending them to commutative k-cubes, for all k, forming thus an exact system of functors universal within the connected ones; or, in other words, a system of simplicial satellites. The tool we develop here for this extension is the homotopy kernel of a commutative k-dimensional cubic diagram, generalising the homotopy kernel of a map; its 2-dimensional version has already been proved essential in other homotopical topics. 相似文献
106.
Alberto Cavicchioli Friedrich Hegenbarth Dusan Repovs 《Transactions of the American Mathematical Society》1997,349(10):4007-4019
We study the homotopy type of closed connected topological -manifolds whose fundamental group is that of an aspherical surface . Then we use surgery theory to show that these manifolds are -cobordant to connected sums of simply-connected manifolds with an -bundle over .
107.
Gábor Elek 《K-Theory》1998,13(1):1-22
We prove that, for any exact category M, any element of K1(M)can be described in terms of a pair of admissible monomorphisms A X, B Y and an isomorphism :A X/A Y B Y/B X. 相似文献
108.
《印度化学会志》2023,100(3):100937
Main core part of the research is to develop a novel mathematical model of MHD-Maxwell nanofluid over a stretching and shrinking surface. The stretching ratio, velocity slip and convective boundary conditions are also incorporated. The PDE's with associative boundary conditions are deduced into coupled highly non-linear ODE's by utilizing suitable transformations. The deduced dimensionless sets of Ordinary differential equations are solved by Optimal-Homotopy Analysis Method (OHAM). Behavior of pertinent parameters on the velocity, temperature and concentration fields as well as important aspects skin friction, Nusselt number and Sherwood number are recorded in Table 2. Outcomes declared that role of stretching ratio plays a prominent role in stretching surfaces its clearly recorded in Table 1(a & b). 相似文献
109.
Rui Miguel Saramago 《Proceedings of the American Mathematical Society》2008,136(8):2699-2709
We use Dieudonné theory for periodically graded Hopf rings to determine the Dieudonné ring structure of the -graded Morava -theory , with an odd prime, when applied to the -spectrum (and to ). We also expand these results in order to accomodate the case of the full Morava -theory .
110.
Jyh-Haur Teh 《Transactions of the American Mathematical Society》2008,360(6):3263-3285
We generalize the Harnack-Thom theorem to relate the ranks of the Lawson homology groups with -coefficients of a real quasiprojective variety with the ranks of its reduced real Lawson homology groups. In the case of zero-cycle group, we recover the classical Harnack-Thom theorem and generalize the classical version to include real quasiprojective varieties. We use Weil's construction of Picard varieties to construct reduced real Picard groups, and Milnor's construction of universal bundles to construct some weak models of classifying spaces of some cycle groups. These weak models are used to produce long exact sequences of homotopy groups which are the main tool in computing the homotopy groups of some cycle groups of divisors. We obtain some congruences involving the Picard number of a nonsingular real projective variety and the rank of its reduced real Lawson homology groups of divisors.