全文获取类型
收费全文 | 7010篇 |
免费 | 674篇 |
国内免费 | 486篇 |
专业分类
化学 | 368篇 |
晶体学 | 10篇 |
力学 | 551篇 |
综合类 | 167篇 |
数学 | 5128篇 |
物理学 | 1946篇 |
出版年
2024年 | 82篇 |
2023年 | 60篇 |
2022年 | 109篇 |
2021年 | 147篇 |
2020年 | 180篇 |
2019年 | 181篇 |
2018年 | 181篇 |
2017年 | 202篇 |
2016年 | 200篇 |
2015年 | 146篇 |
2014年 | 279篇 |
2013年 | 480篇 |
2012年 | 309篇 |
2011年 | 300篇 |
2010年 | 284篇 |
2009年 | 380篇 |
2008年 | 431篇 |
2007年 | 426篇 |
2006年 | 394篇 |
2005年 | 312篇 |
2004年 | 283篇 |
2003年 | 321篇 |
2002年 | 313篇 |
2001年 | 288篇 |
2000年 | 288篇 |
1999年 | 236篇 |
1998年 | 208篇 |
1997年 | 145篇 |
1996年 | 146篇 |
1995年 | 74篇 |
1994年 | 87篇 |
1993年 | 70篇 |
1992年 | 69篇 |
1991年 | 76篇 |
1990年 | 57篇 |
1989年 | 44篇 |
1988年 | 49篇 |
1987年 | 33篇 |
1986年 | 29篇 |
1985年 | 42篇 |
1984年 | 47篇 |
1983年 | 27篇 |
1982年 | 22篇 |
1981年 | 27篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 16篇 |
1977年 | 8篇 |
1976年 | 14篇 |
1974年 | 7篇 |
排序方式: 共有8170条查询结果,搜索用时 78 毫秒
41.
Svante Janson 《Annals of Combinatorics》2009,12(4):417-447
We study the space requirements of a sorting algorithm where only items that at the end will be adjacent are kept together. This is equivalent to the following combinatorial problem: Consider a string of fixed length n that starts as a string of 0’s, and then evolves by changing each 0 to 1, with the n changes done in random order. What is the maximal number of runs of 1’s? We give asymptotic results for the distribution and mean. It turns out that, as in many problems involving a maximum, the maximum is asymptotically normal, with fluctuations of order n 1/2, and to the first order well approximated by the number of runs at the instance when the expectation is maximized, in this case when half the elements have changed to 1; there is also a second order term of order n 1/3. We also treat some variations, including priority queues and sock-sorting. The proofs use methods originally developed for random graphs. 相似文献
42.
三体纯态的纠缠度与量子控制隐形传送的理论分析 总被引:1,自引:0,他引:1
对三体纯态,V.Coffman等提出了分布纠缠的概念及纠缠的度量"tangle".本文由变换算符出发,以三粒子作为量子通道对一个任意的粒子态实现控制隐形传送为例,给出纠缠度与量子控制隐形传态之间满足的关系. 相似文献
43.
We study the efficiency of parallel tempering Monte Carlo technique for calculating true ground states of the Edwards-Anderson spin glass model. Bimodal and Gaussian bond distributions were considered in two- and three-dimensional lattices. By a systematic analysis we find a simple formula to estimate the values of the parameters needed in the algorithm to find the GS with a fixed average probability. We also study the performance of the algorithm for single samples, quantifying the difference between samples where the GS is hard, or easy, to find. The GS energies we obtain are in good agreement with the values found in the literature. Our results show that the performance of the parallel tempering technique is comparable to more powerful heuristics developed to find the ground state of Ising spin glass systems. 相似文献
44.
45.
V. A. Yudin 《Mathematical Notes》1998,63(2):279-282
46.
We consider orthogonal polynomials , where n is the degree of the polynomial and N is a discrete parameter. These polynomials are orthogonal with respect to a varying weight WN which depends on the parameter N and they satisfy a recurrence relation with varying recurrence coefficients which we assume to be varying monotonically as N tends to infinity. We establish the existence of the limit and link this limit to an external field for an equilibrium problem in logarithmic potential theory. 相似文献
47.
Z.Wazir 《中国物理C(英文版)》2010,34(10)
I discuss the results from a study of the central 12CC collisions at 4.2 A GeV/c.The data have been analyzed using a new method based on the Random Matrix Theory.The simulation data coming from the Ultra Relativistic Quantum Molecular Dynamics code were used in the analyses.I found that the behavior of the nearest neighbor spacing distribution for the protons,neutrons and neutral pions depends critically on the multiplicity of secondary particles for simulated data.I conclude that the obtained results offer the possibility of fixing the centrality using the critical values of the multiplicity. 相似文献
48.
The stochastic integrals of M- type 2 Banach valued random functions w.r.t. compensated Poisson random measures introduced in (Rüdiger, B., 2004, In: Stoch. Stoch. Rep., 76, 213–242.) are discussed for general random functions. These are used to solve stochastic integral equations driven by non Gaussian Lévy noise on such spaces. Existence and uniqueness of the path wise solutions are proven under local Lipshitz conditions for the drift and noise coefficients on M-type 2 as well as general separable Banach spaces. The continuous dependence of the solution on the initial data as well as on the drift and noise coefficients are shown. The Markov properties for the solutions are analyzed. 相似文献
49.
The Pullback Asymptotic Behavior of the Solutions for 2D Nonautonomous G-Navier-Stokes Equations
下载免费PDF全文
![点击此处可从《advances in applied mathematics and mechanics.》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jinping Jiang Yanren Hou & Xiaoxia Wang 《advances in applied mathematics and mechanics.》2012,4(2):223-237
The pullback asymptotic behavior of the solutions for 2D Nonautonomous
G-Navier-Stokes equations is studied, and the existence of its $L^2$-pullback attractors on some bounded domains with Dirichlet boundary conditions
is investigated by using the measure of noncompactness. Then the estimation of
the fractal dimensions for the 2D G-Navier-Stokes equations is given. 相似文献
50.
The supersonic and hypersonic.laminar and turbulent vi-scous separated flows over two and three-dimensional com-pression corners are solved by the antidissipative explicit-implicit difference scheme presented in this paper.The re-sults obtained show that a high accuracy has been achieved bythis method and the time needed for computation is greatlyreduced. 相似文献