全文获取类型
收费全文 | 2807篇 |
免费 | 93篇 |
国内免费 | 123篇 |
专业分类
化学 | 217篇 |
晶体学 | 1篇 |
力学 | 138篇 |
综合类 | 5篇 |
数学 | 1683篇 |
物理学 | 979篇 |
出版年
2024年 | 4篇 |
2023年 | 22篇 |
2022年 | 59篇 |
2021年 | 33篇 |
2020年 | 70篇 |
2019年 | 72篇 |
2018年 | 81篇 |
2017年 | 55篇 |
2016年 | 52篇 |
2015年 | 42篇 |
2014年 | 135篇 |
2013年 | 240篇 |
2012年 | 96篇 |
2011年 | 162篇 |
2010年 | 134篇 |
2009年 | 180篇 |
2008年 | 217篇 |
2007年 | 186篇 |
2006年 | 134篇 |
2005年 | 99篇 |
2004年 | 83篇 |
2003年 | 85篇 |
2002年 | 63篇 |
2001年 | 48篇 |
2000年 | 52篇 |
1999年 | 45篇 |
1998年 | 58篇 |
1997年 | 48篇 |
1996年 | 53篇 |
1995年 | 34篇 |
1994年 | 35篇 |
1993年 | 29篇 |
1992年 | 33篇 |
1991年 | 32篇 |
1990年 | 23篇 |
1989年 | 33篇 |
1988年 | 28篇 |
1987年 | 18篇 |
1986年 | 16篇 |
1985年 | 15篇 |
1984年 | 22篇 |
1983年 | 12篇 |
1982年 | 18篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1973年 | 4篇 |
排序方式: 共有3023条查询结果,搜索用时 0 毫秒
211.
The consistency index in reciprocal matrices: Comparison of deterministic and statistical approaches
When checking the inconsistency level of a positive reciprocal matrix Saaty uses a deterministic criterion based on two parameters, a benchmark (the average), and a consistency level, usually 10%. Using results from a simulation experiment with 100,000 positive random reciprocal matrices of size varying from 3 to 15, we developed a probabilistic criterion and compare it to Saaty’s index. We found that if a positive reciprocal matrix is consistent according to the deterministic criterion is also consistent according to the probabilistic criterion only if we accept a higher than usual probability of Type I error. Reducing this error implies that the benchmark must be a small percentile of the probability distribution of the consistency index. 相似文献
212.
Cenap Özel Erol Yılmaz Hünkar Kayhan Aliekber Aktağ 《International Journal of Theoretical Physics》2008,47(12):3101-3107
In this paper, the entanglement properties of a system of two atoms inside an optical cavity in a stochastic interaction with
field are studied by the Jaynes-Cummings Model. The phase telegraph noise is considered as a noise term and an exact solution
to the model is obtained. The solution reveals the resulting decoherence effects of the noise on the entanglement properties
of the system. It shows that under the noise the individual atoms do not entangle with the cavity field. However, a strong
atom-atom entanglement is observed in a stationary state. It is seen that a relatively strong noise is cooperative in the
construction of the steady state atom-atom entanglement. 相似文献
213.
In the article we undertook the attempt of using the theory of random fields in the analysis of the separation process of particles in non-contiguous systems. The presentation of the complete model is a complicated problem. We can say that this article is start point of the theory, which will be supplemented gradually in the future. The separation process of particles on sieves is a phenomenon with random character. It is a result of random character of cleaned mixture and the nature of the separation process. Undoubtedly, an important part is played by the theory of random fields in which system-events, inherently not determined, are described in undetermined-probabilistic way. However, we can perceive one paradox in such actions – correctly constructed probabilistic models serve to impose deterministic frames on the given random process. We can say that stochastic models generate the matrix of the causal-consecutive dependence, which will give the ability of controlling a given process. 相似文献
214.
Yevgeniy Kovchegov 《Journal of Theoretical Probability》2008,21(2):437-448
We consider a multi-particle generalization of linear edge-reinforced random walk (ERRW). We observe that in absence of exchangeability,
new techniques are needed in order to study the multi-particle model. We describe an unusual coupling construction associated
with the two-point edge-reinforced process on ℤ and prove a form of recurrence: the two particles meet infinitely often a.s.
This research was supported in part by NSF VIGRE Grant DMS 9983726 at UCLA. 相似文献
215.
We consider supplier diversification in an EOQ type inventory setting with multiple suppliers and binomial yields. We characterize the optimal policy for the model and show that, in this case, it does not pay to diversify, in contrast to previous results in the random yield literature. 相似文献
216.
Shahar Mendelson 《Random Structures and Algorithms》2005,27(1):25-45
We investigate a new notion of embedding of subsets of {?1,1}n in a given normed space, in a way which preserves the structure of the given set as a class of functions on {1, …, n}. This notion is an extension of the margin parameter often used in Nonparametric Statistics. Our main result is that even when considering “small” subsets of {?1, 1}n, the vast majority of such sets do not embed in a better way than the entire cube in any normed space that satisfies a minor structural assumption. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2005 相似文献
217.
Counting labelled planar graphs, and typical properties of random labelled planar graphs, have received much attention recently. We start the process here of extending these investigations to graphs embeddable on any fixed surface S. In particular we show that the labelled graphs embeddable on S have the same growth constant as for planar graphs, and the same holds for unlabelled graphs. Also, if we pick a graph uniformly at random from the graphs embeddable on S which have vertex set {1,…,n}, then with probability tending to 1 as n→∞, this random graph either is connected or consists of one giant component together with a few nodes in small planar components. 相似文献
218.
219.
本文提出了随机点场理论用于研究含有随机夹杂的统计非均匀介质。本文不同于其它作者,一般均将随机理论建立在Eshelby的等效夹杂原理之上,而这里是建立在Kunin的微结构理论基础之上。作为理论的一个应用,本文对复合材料的有效模量及夹杂内部及周围微观场进行了计算。 相似文献
220.
We study the stationary points of what is known as the lattice Landau gauge fixing functional in one-dimensional compact U(1) lattice gauge theory, or as the Hamiltonian of the one-dimensional random phase XY model in statistical physics. An analytic solution of all stationary points is derived for lattices with an odd number of lattice sites and periodic boundary conditions. In the context of lattice gauge theory, these stationary points and their indices are used to compute the gauge fixing partition function, making reference in particular to the Neuberger problem. Interpreted as stationary points of the one-dimensional XY Hamiltonian, the solutions and their Hessian determinants allow us to evaluate a criterion which makes predictions on the existence of phase transitions and the corresponding critical energies in the thermodynamic limit. 相似文献