全文获取类型
收费全文 | 4492篇 |
免费 | 612篇 |
国内免费 | 295篇 |
专业分类
化学 | 190篇 |
晶体学 | 6篇 |
力学 | 114篇 |
综合类 | 70篇 |
数学 | 2997篇 |
物理学 | 2022篇 |
出版年
2025年 | 8篇 |
2024年 | 43篇 |
2023年 | 48篇 |
2022年 | 98篇 |
2021年 | 119篇 |
2020年 | 127篇 |
2019年 | 116篇 |
2018年 | 125篇 |
2017年 | 101篇 |
2016年 | 137篇 |
2015年 | 80篇 |
2014年 | 259篇 |
2013年 | 319篇 |
2012年 | 250篇 |
2011年 | 255篇 |
2010年 | 278篇 |
2009年 | 307篇 |
2008年 | 374篇 |
2007年 | 343篇 |
2006年 | 298篇 |
2005年 | 234篇 |
2004年 | 172篇 |
2003年 | 211篇 |
2002年 | 164篇 |
2001年 | 147篇 |
2000年 | 130篇 |
1999年 | 111篇 |
1998年 | 102篇 |
1997年 | 84篇 |
1996年 | 69篇 |
1995年 | 35篇 |
1994年 | 34篇 |
1993年 | 22篇 |
1992年 | 22篇 |
1991年 | 17篇 |
1990年 | 12篇 |
1989年 | 10篇 |
1988年 | 17篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 19篇 |
1984年 | 9篇 |
1983年 | 13篇 |
1982年 | 14篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1976年 | 8篇 |
1975年 | 6篇 |
排序方式: 共有5399条查询结果,搜索用时 15 毫秒
1.
本文目的在于建立确定R ̄d中Hausdorff维数dim和packing维数Dim的两个命题(定理1和定理2),进而寻求R ̄d中Hausdorff维数dim与packing维数Dim相等的条件;这使得我们能够引入分形测度的测度论定义。 相似文献
2.
The fluctuation and relative fluctuation of entanglement entropy of a bipartite system for Dirac fields in noninertial frames are investigated. It is shown that the fluctuation and relative fluctuation of entanglement entropy are observer-dependent, which depend on their observed frames. It is found that both the fluctuation and relative fluctuation of entanglement entropy become more noticeable with the increasing of the subsystem's acceleration. We also find that the entanglement entropy always has fluctuation regardless of the initial state parameter and for any magnitude of the acceleration. We argue that the statistical mean for the measurement of entanglement entropy relates to the accelerated motion of the observer. 相似文献
3.
C. S. Unnikrishnan 《Pramana》2005,65(3):359-379
I discuss in detail the result that the Bell’s inequalities derived in the context of local hidden variable theories for discrete
quantized observables can be satisfied only if a fundamental conservation law is violated on the average. This result shows
that such theories are physically nonviable, and makes the demarcating criteria of the Bell’s inequalities redundant. I show
that a unique correlation function can be derived from the validity of the conservation law alone and this coincides with
the quantum mechanical correlation function. Thus, any theory with a different correlation function, like any local hidden
variable theory, is incompatible with the fundamental conservation laws and space-time symmetries. The results are discussed
in the context of two-particle singlet and triplet states, GHZ states, and two-particle double slit interferometry. Some observations
on quantum entropy, entanglement, and nonlocality are also discussed. 相似文献
4.
In this Letter, we put forward a new nontrivial three-step strategy for joint remote preparation of arbitrary two-qudit states (JRSP) in a deterministic manner from a spatially separated multi-sender to one receiver. The scheme is then extended to the arbitrary multi-qudit case. In our schemes, various partially entangled GHZ-like states with arbitrary complex parameters are used as the quantum channels. It overcomes state preparation failure leading to the loss of valuable quantum channel resource and ensures the prepared data available for the remote terminals under extreme conditions such as limited number of quantum channels and limited quantum information processing technologies. 相似文献
5.
Zhenxin Liu 《数学研究通讯:英文版》2023,39(3):476-500
The limit distribution for homogeneous Markov processes is studied extensively and well understood, but it is not the case for inhomogeneous
Markov processes. In this paper, we review some recent results on inhomogeneous Markov processes generated by non-autonomous stochastic (partial)
differential equations (SDE in short). Under some suitable conditions, we show
that the distribution of recurrent solutions of SDEs constitutes the limit distribution of the corresponding inhomogeneous Markov processes. 相似文献
6.
We investigate the sudden birth and sudden death of entanglement of two qubits interacting with uncorrelated structured reservoirs. The system is initially prepared in two-qubit extended Werner-like state. We work out the dependence of the entanglement dynamics on both non-Markovian environments and the purity of initial state, and show that non-Markovian environments and the purity can control the time of the two-qubit entanglement sudden death and the reservoirs' entanglement sudden birth. Furthermore, under the conditions of different purity and initial entangIement, the revival of qubits' entanglement can manifest before, simultaneously or even after the disentanglement of their corresponding reservoirs. 相似文献
7.
ZHAO Hui WANG Zhi-Xi 《理论物理通讯》2007,47(1):45-48
We investigate the entanglement of formation for a class of high-dimensional quantum mixed states. We present a kind of generalized concurrence for a class of high-dimensional quantum pure states such that the entanglement of formation is a monotonically increasing convex function of the generallzed concurrence, from the monotonicity and convexity the entanglement of formafion for a class of high-dimensional mixed states has been calculated analytically, 相似文献
8.
:本文介绍了国际上关于环境电磁学及电磁兼容技术的一些科研进展情况,描述了电磁兼容的动态,最后并提出了若干建议. 相似文献
9.
10.
本文针对列阵元件的特点,提出了对其光谱响应进行整体测试的方法。实测结果与误差分析计算表明,整体测试法是一种准确稳定和易行的方法。 相似文献