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1.
In this paper we consider a system of two two-level atoms interacting with a binomial field in an ideal cavity. We investigate the time evolution of the single atom entropy squeezing, atomic inversion and the linear entropy for the present system. Furthermore, the relationship between the entropy squeezing and the entanglement is investigated. It is shown that the amounts of the nonclassical effects exhibited in the entropy squeezing are dependent on the different initial conditions. The entropy squeezing can give information on the corresponding linear entropy. 相似文献
2.
Xiao GuoHao Yu Yu-Long Jiang Guo-Ping RuDavid Wei Zhang Bing-Zong Li 《Applied Surface Science》2011,257(24):10571-10575
Nickel silicide formation on Si(1 1 0) and Si(1 0 0) substrate was investigated in this paper. It is confirmed that nickel monosilicide (NiSi) starts to form after 450 °C annealing for Si(1 0 0) substrate, but a higher annealing temperature is required for NiSi formation on Si(1 1 0) substrate, which is demonstrated by X-ray diffraction (XRD) and Raman scattering spectroscopy. The higher formation temperature of NiSi is attributed to the larger Ni2Si grain size formed on Si(1 1 0) substrate. Ni silicided Schottky contacts on both Si(1 0 0) and Si(1 1 0) substrates were also fabricated for electrical characteristics evaluation. It clearly reveals that the rectifying characteristics of NiSi/n-Si(1 1 0) Schottky contacts is inferior to that of NiSi/n-Si(1 0 0) Schottky contacts, which is attributed to a lower Schottky barrier height and a rougher contact interface. The formation kinetics for nickel silicide on Si(1 1 0) substrate is also discussed in this paper. 相似文献
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Quantum computers hold the promise of solving certain computational tasks much more efficiently than classical computers. We review recent experimental advances towards a quantum computer with trapped ions. In particular, various implementations of qubits, quantum gates and some key experiments are discussed. Furthermore, we review some implementations of quantum algorithms such as a deterministic teleportation of quantum information and an error correction scheme. 相似文献
7.
L. H. Zhao E. Z. Luo M. Henzler 《Applied Physics A: Materials Science & Processing》1990,50(6):595-602
We extend the range of the interaction between the surface scatterers to the next-nearest neighbours and thus treat the stepped surface as a second-order Markov chain. We employ two interaction parameters to describe the behaviour of the atomic pair correlation function for a two-level system and derive an exact expression for this function. This expression is then used to calculate the profile of the diffracted intensity. The effects of the interaction parameters on the intensity profiles as well as on the terrace width distributions are investigated in detail and compared to the molecular beam epitaxy measurement of Si on a Si(111) surface. The physical meaning of the interaction parameters is also interpreted in terms of the Ising model. 相似文献
8.
Applying the operator a + a+ to the superposed coherent states several times, superpositions of the excited–deexcited coherent states are obtained. Compared with the original superposed coherent states, these new states can have stronger squeezing and anti-bunching effects. The operation a + a+ can also induce squeezing or antibunching effect if the original states do not possess these properties. Calculations about the phase properties, the Q function and the Wigner function reflect the non-classical character of the excited–deexcited states from different aspects. 相似文献
9.
E. Brambilla A. Gatti L.A. Lugiato M.I. Kolobov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(1):127-135
We analyze theoretically spatial structures appearing in the far diffraction zone of the electromagnetic field emitted in
the cavityless parametric down-conversion. We investigate in detail the spatial correlation functions of intensity and demonstrate
the existence of strong quantum correlations between the regions of the far field symmetrical with respect to the optical
axis. Our simplified model allows us to obtain analytical results for some limiting cases. We demonstrate that in the limit
of small diffraction and ideal quantum efficiency of photodetection the noise reduction in the photocurrent difference between
symmetrical regions in the far diffraction field becomes complete at zero frequency of photocurrent fluctuations.
Received 5 February 2001 and Received in final form 11 April 2001 相似文献
10.
H.-y. Fan A. Wünsche 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(3):405-412
We examine the existence of right-hand eigenstates (or eigenkets) of the boson creation operator a
and determine their coordinate and their Bargmann representation. The eigenkets of the creation operator are ultrasingular
and cannot be considered as a limiting case of normalizable states. Applications of these eigenstates as auxiliary states
for purposes of representation of states by path integrals over coherent states are discussed. A completeness relation for
coherent states on paths through the complex plane is derived and special examples of its application are considered.
Received 9 March 2001 and Received in final form 13 June 2001 相似文献