全文获取类型
收费全文 | 7551篇 |
免费 | 1410篇 |
国内免费 | 472篇 |
专业分类
化学 | 2096篇 |
晶体学 | 73篇 |
力学 | 422篇 |
综合类 | 259篇 |
数学 | 2573篇 |
物理学 | 4010篇 |
出版年
2023年 | 53篇 |
2022年 | 138篇 |
2021年 | 259篇 |
2020年 | 226篇 |
2019年 | 216篇 |
2018年 | 223篇 |
2017年 | 361篇 |
2016年 | 374篇 |
2015年 | 310篇 |
2014年 | 469篇 |
2013年 | 660篇 |
2012年 | 466篇 |
2011年 | 511篇 |
2010年 | 434篇 |
2009年 | 459篇 |
2008年 | 478篇 |
2007年 | 476篇 |
2006年 | 403篇 |
2005年 | 397篇 |
2004年 | 354篇 |
2003年 | 284篇 |
2002年 | 243篇 |
2001年 | 241篇 |
2000年 | 200篇 |
1999年 | 152篇 |
1998年 | 149篇 |
1997年 | 101篇 |
1996年 | 111篇 |
1995年 | 114篇 |
1994年 | 69篇 |
1993年 | 73篇 |
1992年 | 59篇 |
1991年 | 53篇 |
1990年 | 38篇 |
1989年 | 28篇 |
1988年 | 45篇 |
1987年 | 29篇 |
1986年 | 27篇 |
1985年 | 22篇 |
1984年 | 29篇 |
1983年 | 10篇 |
1982年 | 16篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1973年 | 5篇 |
排序方式: 共有9433条查询结果,搜索用时 15 毫秒
71.
72.
73.
Robert S. Maier 《Random Structures and Algorithms》1991,2(4):379-420
We analyze the performance of a prototypical scheme for shared storage allocation: two initially empty stacks evolving in a contiguous block of memory of size m. We treat the case in which the stacks are more likely to shrink than grow, but with the probabilities of insertion and deletion allowed to depend arbitrarily on stack height as a fraction of m. New results are obtained on the m → ∞ asymptotics of the stack collision time, and of the final stack heights. The results of Wentzell and Freidlin on the large deviations of Markov chains are used, and the relation of their formalism to the Hamiltonian formulation of classical mechanics is emphasized. Certain results on higher-order asymptotics follow from WKB expansions. 相似文献
74.
75.
在s波超导体绝缘层dx2-y2波超导体结(sId)中,考虑到结界面粗糙散射,运用BogoliubovdeGennes(BdG)方程和FurusakiTsukada(FT)电流公式,计算超导结中的准粒子传输系数和直流Josephson电流.结果表明:sId超导结的直流Josephson电流随温度以及结两侧的相位差变化的关系曲线强烈地依赖于d波超导体的晶轴方位;结界面的粗糙散射对Josephson电流有抑制作用
关键词:
s/I/d超导结
dx2-y2波超导体
直流Josephson电流 相似文献
76.
77.
Determination of a control parameter in a one-dimensional parabolic equation using the method of radial basis functions 总被引:3,自引:0,他引:3
In this work, the method of radial basis functions is used for finding the solution of an inverse problem with source control parameter. Because a much wider range of physical phenomena are modelled by nonclassical parabolic initial-boundary value problems, theoretical behavior and numerical approximation of these problems have been active areas of research. The radial basis functions (RBF) method is an efficient mesh free technique for the numerical solution of partial differential equations. The main advantage of numerical methods which use radial basis functions over traditional techniques is the meshless property of these methods. In a meshless method, a set of scattered nodes are used instead of meshing the domain of the problem. The results of numerical experiments are presented and some comparisons are made with several well-known finite difference schemes. 相似文献
78.
79.
80.
Roland Opfer 《Advances in Computational Mathematics》2006,25(4):357-380
This paper reconstructs multivariate functions from scattered data by a new multiscale technique. The reconstruction uses
standard methods of interpolation by positive definite reproducing kernels in Hilbert spaces. But it adopts techniques from
wavelet theory and shift-invariant spaces to construct a new class of kernels as multiscale superpositions of shifts and scales
of a single compactly supported function φ. This means that the advantages of scaled regular grids are used to construct the
kernels, while the advantages of unrestricted scattered data interpolation are maintained after the kernels are constructed.
Using such a multiscale kernel, the reconstruction method interpolates at given scattered data. No manipulations of the data
(e.g., thinning or separation into subsets of certain scales) are needed. Then, the multiscale structure of the kernel allows
to represent the interpolant on regular grids on all scales involved, with cheap evaluation due to the compact support of
the function φ, and with a recursive evaluation technique if φ is chosen to be refinable. There also is a wavelet-like data
reduction effect, if a suitable thresholding strategy is applied to the coefficients of the interpolant when represented over
a scaled grid. Various numerical examples are presented, illustrating the multiresolution and data compression effects. 相似文献