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101.
The Bak-Sneppen model of co-evolution is used to derive synthetic time series with a priori specified fractal dimension (or Hurst exponent) through a mixing of processes in various lattice dimensions. Both theoretical and numerical analyses concern the avalanches at the critical threshold and provide a model for time series reconstruction that can be tested as an alternative to the classical fractional Brownian motion (fBm) because of differences in properties. New results on critical threshold and avalanche structure are obtained up to Euclidean dimension d=6. The method involves a lattice-based structure and therefore is suitable for the application of parallel computing. 相似文献
102.
Mesfin Asfaw 《Physica A》2007,384(2):346-358
We model a tiny heat engine as a Brownian particle that moves in a viscous medium in a sawtooth potential (with or without load) assisted by alternately placed hot and cold heat baths along its path. We find closed form expression for the steady-state current as a function of the model parameters. This enables us to deal with the energetics of the model and evaluate either its efficiency or its coefficient of performance depending upon whether the model functions either as a heat engine or as a refrigerator, respectively. We also study the way current changes with changes in parameters of interest. When we plot the phase diagrams showing the way the model operates, we not only find regions where it functions as a heat engine and as a refrigerator but we also identify a region where the model functions as neither of the two. 相似文献
103.
We study a simple microscopic model for the one-dimensional stochastic motion of a (non-)relativistic Brownian particle, embedded into a heat bath consisting of (non-)relativistic particles. The stationary momentum distributions are identified self-consistently (for both Brownian and heat bath particles) by means of two coupled integral criteria. The latter follow directly from the kinematic conservation laws for the microscopic collision processes, provided one additionally assumes probabilistic independence of the initial momenta. It is shown that, in the non-relativistic case, the integral criteria do correctly identify the Maxwellian momentum distributions as stationary (invariant) solutions. Subsequently, we apply the same criteria to the relativistic case. Surprisingly, we find here that the stationary momentum distributions differ slightly from the standard Jüttner distribution by an additional prefactor proportional to the inverse relativistic kinetic energy. 相似文献
104.
Room-temperature Ionic Liquids(ILs) have numerous unique properties that differ from those of conventional molecular solvents.Although the unique properties of ILs have been suggested to origin from their microscopic interionic interaction,detailed dynamics of interionic interaction of ILs has not been fully understood.Here,with the Femtosecond Optical Heterodyne-Detected Raman Induced Kerr Effect Spectroscopy(fs-OHD-RIKES),we measured the ultrafast dynamics of the interionic interaction of three typical im... 相似文献
105.
S. Wolfling Y. Kantor 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,12(4):569-577
Distribution of loops in a one-dimensional random walk (RW), or, equivalently, neutral segments in a sequence of positive
and negative charges is important for understanding the low energy states of randomly charged polymers. We investigate numerically
and analytically loops in several types of RWs, including RWs with continuous step-length distribution. We show that for long
walks the probability density of the longest loop becomes independent of the details of the walks and definition of the loops.
We investigate crossovers and convergence of probability densities to the limiting behavior, and obtain some of the analytical
properties of the universal probability density.
Received 8 January 1999 相似文献
106.
We consider a system of diffusing particles on the real line in a quadratic external potential and with a logarithmic interaction potential. The empirical measure process is known to converge weakly to a deterministic measure-valued process as the number of particles tends to infinity. Provided the initial fluctuations are small, the rescaled linear statistics of the empirical measure process converge in distribution to a Gaussian limit for sufficiently smooth test functions. For a large class of analytic test functions, we derive explicit general formulae for the mean and covariance in this central limit theorem by analyzing a partial differential equation characterizing the limiting fluctuations. 相似文献
107.
本文采用了一例特定的Lyapunov函数,来研究带Markov调制的随机微分延迟方程的p阶指数稳定性,并对其几乎必然指数稳定性也进行了探讨. 相似文献
108.
A second-order fluid flow model of a queue with finite capacity buffer and variable net input process is presented, based
on the previous work of Karandikar and Kulkarni (1995). Queue length is modelled as a Brownian motion whose parameters are
controlled by a finite state Markov chain. The process, termed a Markov modulated regulated Brownian motion (MMRBM), provides
analytical solutions for steady state queue length distributions, overflow losses and idleness probabilities using boundary
regulators. Applications of the model include queues with failure-prone servers and ATM statistical multiplexers with variable
traffic loads.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
109.
Ryoki Fukushima 《Journal of statistical physics》2008,133(4):639-657
We consider the Wiener sausage among Poissonian obstacles. The obstacle is called hard if Brownian motion entering the obstacle is immediately killed, and is called soft if it is killed at certain rate. It is known that Brownian motion conditioned to survive among obstacles is confined in a
ball near its starting point. We show the weak law of large numbers, large deviation principle in special cases and the moment
asymptotics for the volume of the corresponding Wiener sausage. One of the consequence of our results is that the trajectory
of Brownian motion almost fills the confinement ball. 相似文献
110.
Athina P. Bougioukou Apostolos P. Leros Vassilios Papakonstantinou 《Applied Mathematical Modelling》2008
This paper presents a new method for modeling amplitude and frequency non-stationary earthquake ground motions using a scalar first order dynamic mean reverting stochastic differential equation driven by Brownian motion with parametric time varying coefficients. It determines the proper relationship between these time varying parametric coefficients and presents the statistical and probability distribution characteristics of the response solution. It demonstrates the applicability of the method by presenting some simulations of amplitude and frequency non-stationary earthquake ground motions. The verification of the amplitude and frequency non-stationary contents of the mean reverting stochastic ground motions is demonstrated using the Hilbert–Huang transform method. Also a corresponding interpretation between the coefficients of the proposed model and the coefficients of the usual oscillatory second order differential equation driven by white Gaussian noise is presented along with some comments how it can be applied to simulate ground motions consistent with acceleration target records such as boxcar, trapezoidal, other exponential functions, or compound and target records at source, near field, and far field distances. 相似文献