全文获取类型
收费全文 | 4152篇 |
免费 | 607篇 |
国内免费 | 294篇 |
专业分类
化学 | 644篇 |
晶体学 | 17篇 |
力学 | 194篇 |
综合类 | 41篇 |
数学 | 1758篇 |
物理学 | 2399篇 |
出版年
2024年 | 9篇 |
2023年 | 29篇 |
2022年 | 279篇 |
2021年 | 398篇 |
2020年 | 176篇 |
2019年 | 108篇 |
2018年 | 114篇 |
2017年 | 117篇 |
2016年 | 140篇 |
2015年 | 103篇 |
2014年 | 168篇 |
2013年 | 287篇 |
2012年 | 171篇 |
2011年 | 216篇 |
2010年 | 195篇 |
2009年 | 246篇 |
2008年 | 265篇 |
2007年 | 245篇 |
2006年 | 229篇 |
2005年 | 212篇 |
2004年 | 168篇 |
2003年 | 175篇 |
2002年 | 161篇 |
2001年 | 113篇 |
2000年 | 88篇 |
1999年 | 93篇 |
1998年 | 75篇 |
1997年 | 89篇 |
1996年 | 41篇 |
1995年 | 31篇 |
1994年 | 43篇 |
1993年 | 29篇 |
1992年 | 38篇 |
1991年 | 21篇 |
1990年 | 21篇 |
1989年 | 23篇 |
1988年 | 25篇 |
1987年 | 18篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1973年 | 3篇 |
1969年 | 4篇 |
排序方式: 共有5053条查询结果,搜索用时 15 毫秒
31.
We investigate a new interpretation for the Navier-Stokes corrections to the hydrodynamic equation of asymmetric interacting particle systems. We consider a system that starts from a measure associated with a profile that is constant along the drift direction. We show that under diffusive scaling the macroscopic behavior of the process is described by a nonlinear parabolic equation whose diffusion coefficient coincides with the diffusion coefficient of the hydrodynamic equation of the symmetric version of the process. 相似文献
32.
33.
利用关于乘积分布密度的相对熵和相对熵率的概念,建立了相依连续型随机变量序列关于参考微分熵的一类强偏差定理,证明中给出了将Laplace变换应用于微分熵强偏差定理的研究的一种途径. 相似文献
34.
David S. Dummit Brett A. Tangedal Paul B. van Wamelen. 《Mathematics of Computation》2004,73(247):1525-1546
Systematic computation of Stark units over nontotally real base fields is carried out for the first time. Since the information provided by Stark's conjecture is significantly less in this situation than the information provided over totally real base fields, new techniques are required. Precomputing Stark units in relative quadratic extensions (where the conjecture is already known to hold) and coupling this information with the Fincke-Pohst algorithm applied to certain quadratic forms leads to a significant reduction in search time for finding Stark units in larger extensions (where the conjecture is still unproven). Stark's conjecture is verified in each case for these Stark units in larger extensions and explicit generating polynomials for abelian extensions over complex cubic base fields, including Hilbert class fields, are obtained from the minimal polynomials of these new Stark units.
35.
The piston problem is investigated in the case where the length of the cylinder is infinite (on both sides) and the ratio m/M is a very small parameter, where m is the mass of one particle of the gaz and M is the mass of the piston. Introducing initial conditions such that the stochastic motion of the piston remains in the average at the origin (no drift), it is shown that the time evolution of the fluids, analytically derived from Liouville equation in a previous work, agrees with the Second Law of thermodynamics. We thus have a non equilibrium microscopical model whose evolution can be explicitly shown to obey the two laws of thermodynamics. 相似文献
36.
对数似然比与整值随机变量序列的一类强律 总被引:2,自引:0,他引:2
本文引进对数似然比作为整值随机变量序列相对于服从几何分布的独立随机变量序列的偏差的一种度量,并通过限制对数似然比给出了样本空间的一个子集.在此子集上得到了一类用不等式表示的强律,其中包含整值随机变量序列与相对熵密度及几何分布的熵函数有关的若干极限性质. 相似文献
37.
Detailed pH-dependent steady state and picosecond time-resolved tryptophan fluorescence studies on thiocyanate and azide complexes
of horseradish peroxidase have been carried out. The fluorescence decay of the single tryptophan in these species was fitted
to a discrete three exponential model. Maximum entropy method analysis also gave three distinct regions of lifetime distributions.
The fast subnanosecond lifetime component was found to have > 97% amplitude contribution while other two longer lifetime components
have small contributions. Small contributions from the nanosecond lifetime components possibly arise from apoprotein impurity
or some small amount of disordered heme conformer of the protein. pH dependence of the fast picosecond lifetime components
was found to show a systematic behavior which has been interpreted in the light of obligatory conformation change associated
with activation of the enzyme at low pH. 相似文献
38.
Let E\subset \Bbb R
s
be compact and let d
n
E
denote the dimension of the space of polynomials of degree at most n in s variables restricted to E . We introduce the notion of an asymptotic interpolation measure (AIM). Such a measure, if it exists , describes the asymptotic behavior of any scheme τ
n
={ \bf x
k,n
}
k=1
dnE
, n=1,2,\ldots , of nodes for multivariate polynomial interpolation for which the norms of the corresponding interpolation operators do
not grow geometrically large with n . We demonstrate the existence of AIMs for the finite union of compact subsets of certain algebraic curves in R
2
. It turns out that the theory of logarithmic potentials with external fields plays a useful role in the investigation. Furthermore,
for the sets mentioned above, we give a computationally simple construction for ``good' interpolation schemes.
November 9, 2000. Date revised: August 4, 2001. Date accepted: September 14, 2001. 相似文献
39.
40.
Hans C. Fogedby 《Journal of statistical physics》1992,69(1-2):411-425
We elaborate in some detail on a new phase space approach to complexity, due to Y.-C. Zhang. We show in particular that the connection between maximal complexity and power law noise or correlations can be derived from a simple variational principle. For a 1D signal we find 1/f noise, in accordance with Zhang. 相似文献