全文获取类型
收费全文 | 1146篇 |
免费 | 28篇 |
国内免费 | 60篇 |
专业分类
化学 | 30篇 |
力学 | 27篇 |
综合类 | 2篇 |
数学 | 1078篇 |
物理学 | 97篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 20篇 |
2021年 | 18篇 |
2020年 | 25篇 |
2019年 | 28篇 |
2018年 | 21篇 |
2017年 | 20篇 |
2016年 | 19篇 |
2015年 | 21篇 |
2014年 | 49篇 |
2013年 | 159篇 |
2012年 | 35篇 |
2011年 | 60篇 |
2010年 | 47篇 |
2009年 | 101篇 |
2008年 | 95篇 |
2007年 | 77篇 |
2006年 | 66篇 |
2005年 | 39篇 |
2004年 | 38篇 |
2003年 | 33篇 |
2002年 | 24篇 |
2001年 | 25篇 |
2000年 | 24篇 |
1999年 | 22篇 |
1998年 | 30篇 |
1997年 | 28篇 |
1996年 | 22篇 |
1995年 | 19篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1234条查询结果,搜索用时 62 毫秒
991.
Ben-yuGuo JieShen Cheng-longXu 《计算数学(英文版)》2005,23(2):113-130
Approximations using the generalized Laguerre polynomials are investigated in this paper. Error estimates for various orthogonal projections are established. These estimates generalize and improve previously published results on the Laguerre approximations. As an example of applications, a mixed Laguerre-Fourier spectral method for the Helmholtz equation in an exterior domain is analyzed and implemented. The proposed method enjoys optimal error estimates, and with suitable basis functions, leads to a sparse and symmetric linear system. 相似文献
992.
We construct some examples of polynomial maps over finite fields that admit subvarieties with a peculiar property: every geometric point is mapped to a fixed point by some iteration of the map, while the whole subvariety is not. Several related open questions are stated and discussed. 相似文献
993.
Animesh Lahiri 《代数通讯》2019,47(3):1099-1101
994.
Multivariate Bessel processes describe the stochastic dynamics of interacting particle systems of Calogero–Moser–Sutherland type and are related with -Hermite and Laguerre ensembles. It was shown by Andraus, Katori, and Miyashita that for fixed starting points, these processes admit interesting limit laws when the multiplicities tend to , where in some cases the limits are described by the zeros of classical Hermite and Laguerre polynomials. In this paper we use SDEs to derive corresponding limit laws for starting points of the form for with in the interior of the corresponding Weyl chambers. Our limit results are a.s. locally uniform in time. Moreover, in some cases we present associated central limit theorems. 相似文献
995.
《Physics letters. A》2019,383(30):125874
Ulmer and Kaissl formulas for the deconvolution of one-dimensional Gaussian kernels are generalized to the three-dimensional case. The generalization is based on the use of the scalar version of the Grad's multivariate Hermite polynomials which can be expressed through ordinary Hermite polynomials. 相似文献
996.
997.
998.
999.
将拉盖尔多项式算符作用在相干态上,构造了拉盖尔多项式算符激发相干态.利用有序算符积分技术,导出了它的归一化系数以及〈a^la^+m〉的计算表达式.采用数值计算方法,讨论了相干态相位角和平均光子数对它的非经典性质的影响.研究结果表明:一阶拉盖尔多项式算符激发相干态呈现出压缩效应、反聚束效应、亚泊松分布和Wigner函数负性等量子特性,并且相干态的相位角对它的量子特性有重要影响;另一方面,随相干态平均光子数增大,它的反聚束效应和亚泊松分布性质逐渐减弱,压缩效应和Wigner函数的负性却先增强,而后又逐渐减弱. 相似文献
1000.
Construction of Laguerre polynomial's photon-added squeezing vacuum state and its quantum properties 下载免费PDF全文
Laguerre polynomial's photon-added squeezing vacuum state is constructed by operation of Laguerre polynomial's photon-added operator on squeezing vacuum state. By making use of the technique of integration within an ordered product of operators, we derive the normalization coefficient and the calculation expression of (a^1a^+). Its statistical properties, such as squeezing, the anti-bunching effect, the sub-Poissonian distribution property, the negativity of Wigner function, etc., are investigated. The influences of the squeezing parameter on quantum properties are discussed. Numerical results show that,firstly, the squeezing effect of the 1-order Laguerre polynomial's photon-added operator exciting squeezing vacuum state is strengthened, but its anti-bunching effect and sub-Poissonian statistical property are weakened with increasing squeezing parameter;secondly, its squeezing effect is similar to that of squeezing vacuum state, but its anti-bunching effect and subPoissonian distribution property are stronger than that of squeezing vacuum state. These results show that the operation of Laguerre polynomial's photon-added operator on squeezing vacuum state can enhance its non-classical properties. 相似文献