全文获取类型
收费全文 | 1052篇 |
免费 | 83篇 |
国内免费 | 110篇 |
专业分类
化学 | 84篇 |
晶体学 | 5篇 |
力学 | 84篇 |
综合类 | 12篇 |
数学 | 904篇 |
物理学 | 156篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 13篇 |
2020年 | 18篇 |
2019年 | 24篇 |
2018年 | 24篇 |
2017年 | 22篇 |
2016年 | 35篇 |
2015年 | 29篇 |
2014年 | 37篇 |
2013年 | 94篇 |
2012年 | 49篇 |
2011年 | 48篇 |
2010年 | 38篇 |
2009年 | 63篇 |
2008年 | 58篇 |
2007年 | 49篇 |
2006年 | 56篇 |
2005年 | 63篇 |
2004年 | 48篇 |
2003年 | 53篇 |
2002年 | 54篇 |
2001年 | 43篇 |
2000年 | 48篇 |
1999年 | 34篇 |
1998年 | 21篇 |
1997年 | 30篇 |
1996年 | 21篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 17篇 |
1992年 | 16篇 |
1991年 | 12篇 |
1990年 | 6篇 |
1989年 | 13篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1972年 | 3篇 |
排序方式: 共有1245条查询结果,搜索用时 31 毫秒
81.
一类积分微分方程概周期解的存在性和唯一性 总被引:1,自引:0,他引:1
考虑具无穷时滞的非线性积分微分方程概周期的存在性和唯一性问题,利用矩阵测度和不动点方法获得了一类方程的概周期的存在性和唯一性的充分条件,推广了相应文献的结果. 相似文献
82.
随机Richlet级数的增长性 总被引:1,自引:0,他引:1
本文构造了全平面上的无限级Dirirchlet级数,使得它对型函数的增长性与一个已知的不同分布随机Dirichlet的增长性相同,从而通过前者增长性与指数,系数的关系可研究后者的增长性. 相似文献
83.
84.
A new algorithm is presented, based on elements of artificial intelligence theory, to determine the fractal properties of the backbone of the incipient infinite cluster. It is found that the fractal dimensionality of the backbone isd
f
BB
=1.61±0.01, the chemical dimensionality isd
t=1.40±0.01, and the fractal dimension of the minimum pathd
min=1.15 ± 0.02 for the two-dimensional triangular lattice. 相似文献
85.
Jian-qin Zhou 《应用数学学报(英文版)》2008,24(2):185-194
Double commutative-step digraph generalizes the double-loop digraph. A double commutative-step digraph can be represented by an L-shaped tile, which periodically tessellates the plane. Given an initial tile L(l, h, x, y), Aguil5 et al. define a discrete iteration L(p) = L(l + 2p, h + 2p, x + p, y + p), p = 0, 1, 2,..., over L-shapes (equivalently over double commutative-step digraphs), and obtain an orbit generated by L(l, h, x,y), which is said to be a procreating k-tight tile if L(p)(p = 0, 1, 2, ~ ~ ~ ) are all k-tight tiles. They classify the set of L-shaped tiles by its behavior under the above-mentioned discrete dynamics and obtain some procreating tiles of double commutative-step digraphs. In this work, with an approach proposed by Li and Xu et al., we define some new discrete iteration over L-shapes and classify the set of tiles by the procreating condition. We also propose some approaches to find infinite families of realizable k-tight tiles starting from any realizable k-tight L-shaped tile L(l, h, x, y), 0 ≤ y - x ≤ 2k + 2. As an example, we present an infinite family of 3-tight optimal double-loop networks to illustrate our approaches. 相似文献
86.
87.
We obtain a solution to the Hilbert boundary value problem in the theory of analytic functions on the half-plane in the case that the coefficients of the boundary condition have countably many discontinuity points of the first kind. We elaborate the two substantially different situations: the series consisting of the jumps of the argument of the coefficient function and the increments of its continuous part converges and this series diverges. Accordingly, Hilbert problems with finite and infinite indices result. We derive formulas for the general solution and investigate the pictures of solvability of these problems. 相似文献
88.
We consider the continued fraction digits as random variables measured with respect to Lebesgue measure. The logarithmically scaled and normalised fluctuation process of the digit sums converges strongly distributional to a random variable uniformly distributed on the unit interval. For this process normalised linearly we determine a large deviation asymptotic. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
89.
Stephen Pankavich 《Mathematical Methods in the Applied Sciences》2008,31(4):375-389
A collisionless plasma is modelled by the Vlasov–Poisson system in one dimension. A fixed background of positive charge, dependent only upon velocity, is assumed and the situation in which the mobile negative ions balance the positive charge as |x| → ∞ is considered. Thus, the total positive charge and the total negative charge are infinite. In this paper, the charge density of the system is shown to be compactly supported. More importantly, both the electric field and the number density are determined explicitly for large values of |x|. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
90.
We present a theory which allows us to justify the existence theorems and derive majorant estimates for solutions of the Cauchy problem for a countable system of partial differential equations. Our results also allow to estimate the maximum existence interval for a solution. 相似文献