全文获取类型
收费全文 | 1895篇 |
免费 | 127篇 |
国内免费 | 80篇 |
专业分类
化学 | 86篇 |
晶体学 | 1篇 |
力学 | 111篇 |
综合类 | 15篇 |
数学 | 1498篇 |
物理学 | 391篇 |
出版年
2023年 | 17篇 |
2022年 | 16篇 |
2021年 | 21篇 |
2020年 | 43篇 |
2019年 | 51篇 |
2018年 | 55篇 |
2017年 | 55篇 |
2016年 | 52篇 |
2015年 | 39篇 |
2014年 | 93篇 |
2013年 | 177篇 |
2012年 | 74篇 |
2011年 | 91篇 |
2010年 | 73篇 |
2009年 | 99篇 |
2008年 | 104篇 |
2007年 | 117篇 |
2006年 | 107篇 |
2005年 | 88篇 |
2004年 | 81篇 |
2003年 | 89篇 |
2002年 | 88篇 |
2001年 | 45篇 |
2000年 | 60篇 |
1999年 | 56篇 |
1998年 | 50篇 |
1997年 | 37篇 |
1996年 | 22篇 |
1995年 | 19篇 |
1994年 | 24篇 |
1993年 | 14篇 |
1992年 | 16篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 15篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有2102条查询结果,搜索用时 62 毫秒
21.
In this paper, we investigate the exact distribution of the waiting time for ther-th ℓ-overlapping occurrence of success-runs of a specified length in a sequence of two state Markov dependent trials. The
probability generating functions are derived explicitly, and as asymptotic results, relationships of a negative binomial distribution
of orderk and an extended Poisson distribution of orderk are discussed. We provide further insights into the run-related problems from the viewpoint of the ℓ-overlapping enumeration
scheme. We also study the exact distribution of the number of ℓ-overlapping occurrences of success-runs in a fixed number
of trials and derive the probability generating functions. The present work extends several properties of distributions of
orderk and leads us a new type of geneses of the discrete distributions. 相似文献
22.
We characterize Poisson and Jacobi structures by means of complete lifts of the corresponding tensors: the lifts have to be
related to canonical structures by morphisms of corresponding vector bundles. Similar results hold for generalized Poisson
and Jacobi structures (canonical structures) associated with Lie algebroids and Jacobi algebroids. 相似文献
23.
Mathematical Notes - 相似文献
24.
In this article we use classical formulas involving the K–Bessel function in two variables to express the Poisson kernel on a Riemannian manifold in terms of the heat kernel. We then use the small time asymptotics of the heat kernel on certain Riemannian manifolds to obtain a meromorphic continuation of the associated Poisson kernel to all values of complex time with identifiable singularities. This result reproves in a different setting by different means a well–known theorem due to Duistermaat and Guillemin [DG 75]. Also, we develop analytic expressions for the heat kernel beyond asymptotic expansions. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
25.
We observe that a term of the WZW-type can be added to the Lagrangian of the Poisson σ-model in such a way that the algebra of the first class constraints remains closed. This leads to a natural generalization of the concept of Poisson geometry. The resulting “WZW–Poisson” manifold M is characterized by a bivector Π and by a closed three-form H such that 1/2[Π,Π]Schouten=H,ΠΠΠ. 相似文献
26.
Steven G. From 《Annals of the Institute of Statistical Mathematics》1991,43(1):167-179
In this paper, a family of estimators for estimating means when mixing two independent Poisson samples is proposed. This family is based on the probability-generating function of the Poisson distribution and is offered as an alternative to the maximum likelihood estimators, which have some drawbacks. These estimators include the method of moments estimators as a special limiting case. 相似文献
27.
Olav Kallenberg 《Stochastic Processes and their Applications》1992,40(2):199-223
From the predictable reduction of a marked point process to Poisson, we derive a similar reduction theorem for purely discontinuous martingales to processes with independent increments. Both results are then used to examine the existence of stochastic integrals with respect to stable Lévy processes, and to prove a variety of time change representations for such integrals. The Knight phenomenon, where possibly dependent but orthogonal processes become independent after individual time changes, emerges as a general principle. 相似文献
28.
29.
Derived Brackets 总被引:3,自引:1,他引:2
Yvette Kosmann-Schwarzbach 《Letters in Mathematical Physics》2004,69(1-3):61-87
We survey the many instances of derived bracket construction in differential geometry, Lie algebroid and Courant algebroid theories, and their properties. We recall and compare the constructions of Buttin and of Vinogradov, and we prove that the Vinogradov bracket is the skew-symmetrization of a derived bracket. Odd (resp., even) Poisson brackets on supermanifolds are derived brackets of canonical even (resp., odd) Poisson brackets on their cotangent bundle (resp., parity-reversed cotangent bundle). Lie algebras have analogous properties, and the theory of Lie algebroids unifies the results valid for manifolds on the one hand, and for Lie algebras on the other. We outline the role of derived brackets in the theory of Poisson structures with background'. 相似文献
30.
Numerical analysis for stochastic age-dependent population equations with Poisson jumps 总被引:1,自引:0,他引:1
In this paper, stochastic age-dependent population equations with Poisson jumps are considered. In general, most of stochastic age-dependent population equations with jumps do not have explicit solutions, thus numerical approximation schemes are invaluable tools for exploring their properties. The main purpose of this paper is to develop a numerical Euler scheme and show the convergence of the numerical approximation solution to the true solution. 相似文献