全文获取类型
收费全文 | 3809篇 |
免费 | 239篇 |
国内免费 | 473篇 |
专业分类
化学 | 53篇 |
力学 | 58篇 |
综合类 | 49篇 |
数学 | 3905篇 |
物理学 | 456篇 |
出版年
2023年 | 51篇 |
2022年 | 23篇 |
2021年 | 38篇 |
2020年 | 79篇 |
2019年 | 104篇 |
2018年 | 107篇 |
2017年 | 98篇 |
2016年 | 116篇 |
2015年 | 95篇 |
2014年 | 184篇 |
2013年 | 342篇 |
2012年 | 109篇 |
2011年 | 202篇 |
2010年 | 154篇 |
2009年 | 266篇 |
2008年 | 319篇 |
2007年 | 262篇 |
2006年 | 232篇 |
2005年 | 225篇 |
2004年 | 172篇 |
2003年 | 191篇 |
2002年 | 186篇 |
2001年 | 131篇 |
2000年 | 122篇 |
1999年 | 127篇 |
1998年 | 116篇 |
1997年 | 123篇 |
1996年 | 63篇 |
1995年 | 42篇 |
1994年 | 32篇 |
1993年 | 20篇 |
1992年 | 12篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 3篇 |
1982年 | 18篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1976年 | 5篇 |
1973年 | 2篇 |
1970年 | 2篇 |
排序方式: 共有4521条查询结果,搜索用时 5 毫秒
81.
Given a braided vector space
, we show that iterated integrals of operator-valued functions satisfying a certain exchange relation give rise to representations of the quantum shuffle algebra built on
. Using the quantum shuffle construction of the 'upper triangular part'
of a quantum shuffle, this provides a simple proof of the result of Bouwknegt, MacCarthy and Pilch saying that integrals of vertex operators acting on certain Fock modules give rise to representations of
. 相似文献
82.
We extend recent theoretical studies of entanglement dynamics in the presence of environmental noise, following the long-time interest of Krzysztof Wodkiewicz in the effects of stochastic models of noise on quantum optical coherences. We investigate the quantum entanglement dynamics of two spins in the presence of classical Ornstein-Uhlenbeck noise, obtaining exact solutions for evolution dynamics. We consider how entanglement can be affected by non-Markovian noise, and discuss several limiting cases. 相似文献
83.
Two mutually conjugated tripartite entangled states and their fractional Fourier transformation kernel 下载免费PDF全文
We newly construct two mutually-conjugate tripartite entangled state representations,based on which we propose the formulation of three-mode entangled fractional Fourier transformation(EFFT) and derive the transformation kernel.The EFFT’s additivity property is proved and the eigenmode of EFFT is derived.As an application,we calculate the EFFT of the three-mode squeezed vacuum state. 相似文献
84.
John M. Myers 《Foundations of Physics》2006,36(7):1012-1035
Motivated by a recent proof of free choices in linking equations to the experiments they describe, I clarify some relations among purely mathematical entities featured in quantum mechanics (probabilities, density operators, partial traces, and operator-valued measures), thereby allowing applications of these entities to the modeling of a wider variety of physical situations. I relate conditional probabilities associated with projection-valued measures to conditional density operators identical, in some cases but not in others, to the usual reduced density operators. While a fatal obstacle precludes associating conditional density operators with general non-projective measures, tensor products of general positive operator-valued measures (POVMs) are associated with conditional density operators. This association together with the free choice of probe particles allows a postulate of state reductions to be replaced by a theorem. An application shows an equivalence between one form of quantum key distribution and another with respect to certain eavesdropping attacks. 相似文献
85.
Gordon W. Cook 《Fuzzy Sets and Systems》1986,20(3):355-364
Probability distributions associated with several ‘ply’-operators are discussed. These exact distributions are compared with relevant Gaussian approximations. 相似文献
86.
Summary Further properties are derived for a class of invariant polynomials with several matrix arguments which extend the zonal polynomials.
Generalized Laguerre polynomials are defined, and used to obtain expansions of the sum of independent noncentral Wishart matrices
and an associated generalized regression coefficient matrix. The latter includes thek-class estimator in econometrics. 相似文献
87.
用分析方法研究紧的度量空间上的一类Feller算子P的遍历性质。通过P的转移概率函数π(·,·),给出了P的极小遍历集的特征。利用Riesz表示定理和平均遍历定理证明了紧的度量空间上具有遍历测度的算子P有几乎稠密的轨道。此外,在P的支集相交这一条件下,得到了算子P具有惟一不变概 相似文献
88.
89.
O.M. Lyulin V.I. Perevalov H. Tran J.-Y. Mandin V. Dana L. Rgalia-Jarlot X. Thomas D. Dcatoire 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(17):1815-1824
Using the Fourier transform spectra of the acetylene molecule recorded near 1.5-μm, the intensities of 111 lines belonging to seven hot bands of the main isotopologue 12C2H2 have been retrieved by means of a multispectrum fitting procedure. Considering the density of lines in the spectra, and the fact that the measured bands are the weakest observed, the accuracy of the measurements is around 10%. At first stage, an empirical treatment of these data has been performed, leading to the vibrational transition dipole moment squared and some Herman–Wallis coefficients. Then the measured line intensities of this work and collected ones from the literature have been treated simultaneously within the framework of the effective operator approach. 相似文献
90.
Trace formulas for pairs of self-adjoint, maximal dissipative and accumulative as well as other types of resolvent comparable operators are obtained. In particular, the existence of a complex-valued spectral shift function for a pair {H′,H} of maximal accumulative operators has been proved. We investigate also the existence of a real-valued spectral shift function. Moreover, we treat in detail the case of additive trace class perturbations. Assuming that H and H′=H+V are maximal accumulative and V is trace class, we prove the existence of a summable complex-valued spectral shift function. We also obtain trace formulas for pairs {H,H?}assuming only that H and H?are resolvent comparable. In this case the determinant of the characteristic function of H is involved in trace formulas. 相似文献