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61.
We develop large-deviation results with explicit order terms and Cramér's series for nondegenerate U-statistics of degree m under Cramér-type conditions on the kernel. The method of the proof is based on the contraction technique of Keener, Robinson, and Weber [15], which is a natural generalization of the classical method of Cramér [10]. Other techniques used in the proofs include truncation, decoupling inequalities, Borell's inequality for Rademacher chaos, and a partitioning method to bound the degenerate remainder term. 相似文献
62.
We describe exact solutions of the Einstein field equations invariant under a non-Abelian two-dimensional Lie algebra of Killing
fields. A subclass of these gravitational fields have a wavelike character. We show that they have spin 1. We also discuss
some indirect observational effects. In particular, we show that vector cosmological perturbations can no longer be negligible
in the presence of topological defects, which can be verified by examining the anisotropies of the cosmic microwave background.
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 152, No. 2, pp. 225–240, August, 2007. 相似文献
63.
基于多项式组主项解耦消元法 ,将几何定理的假设条件 (多项式组 PS)化为主项只含主变元的三角型多项式组 DTS,可得到定理命题成立的不含变元的非退化条件 ,即充分必要或更接近充分必要的非退化条件 .由于多项式主系数不含变元 ,已不存在 DTS多项式之间的约化问题 ,故方法有普遍意义 .文中例为西姆松定理的机器证明 . 相似文献
64.
Biplab Bhawal 《Pramana》2004,63(4):645-662
The Caltech-MIT joint LIGO project is operating three long-baseline interferometers (one of 2 km and two of 4 km) in order
to unambiguously measure the infinitesimal displacements of isolated test masses which convey the signature of gravitational
waves from astrophysical sources. An interferometric gravitational wave detector like LIGO is a complex, non-linear, coupled,
dynamic system. This article summarizes various interesting design characteristics of these detectors and techniques that
were implemented in order to reach and maintain its operating condition. Specifically, the following topics are discussed:
(i) length sensing and control, (ii) alignment sensing and control and (iii) thermal lensing which changes the performance
and operating point of the interferometer as the input power to LIGO is increased. 相似文献
65.
Freeman Dyson has questioned whether any conceivable experiment in the real universe can detect a single graviton. If not, is it meaningful to talk about gravitons as physical entities? We attempt to answer Dyson’s question and find it is possible concoct an idealized thought experiment capable of detecting one graviton; however, when anything remotely resembling realistic physics is taken into account, detection becomes impossible, indicating that Dyson’s conjecture is very likely true. We also point out several mistakes in the literature dealing with graviton detection and production. 相似文献
66.
67.
J. I. Ramos 《Archive of Applied Mechanics (Ingenieur Archiv)》1995,65(8):548-563
Summary The nonlinear dynamics of axisymmetric, inviscid, incompressible, thin, annular liquid jets subjected to fluctuating body forces is studied numerically by means of an adaptive finite difference method which maps the time-dependent, curvilinear geometry of the jet into a unit square. The fluctuating body forces may arise from fluctuations in the gravitational acceleration in inertial frames or from the acceleration of a non-inertial frame of reference which translates parallelly to an inertial one. It is shown that both the pressure coefficient and the axial location at which the annular jet becomes a solid one are periodic functions of time with a period equal to that of the imposed body force fluctuations, and that their magnitude increases as the amplitude of the body force fluctuations is increased. It has also been shown that, for both intermittent, sinusoidal or rectangular excitations, increases in the frequency of the excitation result in the creation of superharmonics, broad, albeit peaked, spectra, and closed phase planes with many loops.The research reported in this paper was supported by Project PB91-0767 from the D.G.I.C.Y.T. of Spain. 相似文献
68.
重力场中的大气处于非平衡态,其温度是空间的函数,不同的等温面之间要产生热流,从而改变熵的空间分布。本文推导出重力场中的熵产生公式,并描绘出熵产生随高度变化的近似曲线。 相似文献
69.
To recognize gravitational wave lensing events and being able to differentiate between similar lens models will be of crucial importance once one will be observing several lensing events of gravitational waves per year. In this work, the lensing of gravitational waves is studied in the context of LISA sources and wave-optics regime. While different papers before the studied microlensing effects enhanced by simultaneous strong lensing, the focus is on frequency (time) dependent phase effects produced by one lens that will be visible with only one lensed signal. It is shows how, in the interference regime (i.e., when interference patterns are present in the lensed image), one is able to i) distinguish a lensed waveform from an unlensed one, and ii) differentiate between different lens models. In pure wave-optics, on the other hand, the feasibility of the study depends on the signal-to-noise ratio of the signal and/or the amplitude of the lensing effect. To achieve these goals, the phase of the amplification factor of the different lens models and its effect on the unlensed waveform is studied, and the signal-to-noise calculation to provide some quantitative examples is exploited. 相似文献
70.
Contaminant transport in the upper layers of soil during the multiple cycles of short infiltration and prolonged redistribution
is investigated. Analytical solutions for the two typical problems encountered in agricultural engineering are derived. The
first problem considers the penetration of fertilizer initially applied at the soil surface. The second one is the propagation
of contaminant injected with the applied water. Explicit analytical expressions for the solute concentration are obtained
under assumptions of one-dimensional gravitational flow and advective solute transport under equilibrium conditions. The properties
of the solute penetration are analyzed for the case of contaminant initially applied at the soil surface and picked up by
the water flow during ten infiltration–redistribution cycles.
P. Indelman - (deceased) 相似文献