全文获取类型
收费全文 | 7589篇 |
免费 | 328篇 |
国内免费 | 485篇 |
专业分类
化学 | 162篇 |
力学 | 594篇 |
综合类 | 45篇 |
数学 | 6652篇 |
物理学 | 949篇 |
出版年
2024年 | 15篇 |
2023年 | 104篇 |
2022年 | 109篇 |
2021年 | 99篇 |
2020年 | 196篇 |
2019年 | 215篇 |
2018年 | 198篇 |
2017年 | 185篇 |
2016年 | 193篇 |
2015年 | 165篇 |
2014年 | 337篇 |
2013年 | 806篇 |
2012年 | 295篇 |
2011年 | 460篇 |
2010年 | 380篇 |
2009年 | 570篇 |
2008年 | 557篇 |
2007年 | 488篇 |
2006年 | 387篇 |
2005年 | 325篇 |
2004年 | 266篇 |
2003年 | 307篇 |
2002年 | 226篇 |
2001年 | 195篇 |
2000年 | 211篇 |
1999年 | 188篇 |
1998年 | 169篇 |
1997年 | 167篇 |
1996年 | 127篇 |
1995年 | 77篇 |
1994年 | 75篇 |
1993年 | 37篇 |
1992年 | 31篇 |
1991年 | 28篇 |
1990年 | 26篇 |
1989年 | 23篇 |
1988年 | 17篇 |
1987年 | 19篇 |
1986年 | 12篇 |
1985年 | 27篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1975年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有8402条查询结果,搜索用时 15 毫秒
71.
Haibo Cui Haiyan Yin Jinshun Zhang Changjiang Zhu 《Journal of Differential Equations》2018,264(7):4564-4602
In this paper, we are concerned with the asymptotic behavior of solutions to the system of Euler equations with time-depending damping, in particular, include the constant coefficient damping. We rigorously prove that the solutions time-asymptotically converge to the diffusion wave whose profile is self-similar solution to the corresponding parabolic equation, which justifies Darcy's law. Compared with previous results about Euler equations with constant coefficient damping obtained by Hsiao and Liu (1992) [2], and Nishihara (1996) [9], we obtain a general result when the initial perturbation belongs to the same space, i.e. . Our proof is based on the classical energy method. 相似文献
72.
一个包含Euler函数及k阶Smarandache ceil函数的方程及其正整数解 总被引:3,自引:0,他引:3
朱敏慧 《纯粹数学与应用数学》2009,25(2):414-416
设k≥2为给定的整数.对任意正整数n,k阶Smarandache ceil函数Sk(n)定义为Sk(n)=min{x:x∈N,n|x^k}.本文的主要目的是利用初等方法研究函数方程Sk(n)=Ф(n)的可解性,并给出该方程的所有正整数解,其中Ф(n)为Euler函数. 相似文献
73.
We analytically study the quantum phase diagrams of ultracold dipolar Bose gases in an optical square lattice at zero temperature by using the generalized effective-potential Landau theory (GEPLT). For a weak nearest-neighbor repulsion, our analytical results are better than the third-order strong-coupling expansion theory calculation. In contrast to a previous quantum Monte Carlo (QMC) simulation, we analytically calculate phase transition boundaries up to the third-order hopping, which are in excellent agreement with QMC simulations for second-order phase transition. 相似文献
74.
Balasubramanian Sury 《Rendiconti del Circolo Matematico di Palermo》2009,58(1):99-108
We apply group actions to some natural situations like the natural ‘linear’ action of GL
r
(Z
n
) and some of its subgroups to derive number-theoretic identities like
.
相似文献
75.
Sheree T. Sharpe 《Mathematical Thinking and Learning》2019,21(1):78-84
In this study, the author examined student attempts to translate a verbal problem into an algebraic statement relating two variables, after they had solved an arithmetic question from the same problem. A total of 645 students from New England (U.S.A.) answered the problem on a mathematics assessment administered at the beginning of the school year. Among students who could solve the arithmetic part of the problem, the use of variables in the correct conventional notation appeared from grade 7 and continuously increased through grade 9. These results suggest that there is a relationship between students’ arithmetic understanding and translating verbal problems into algebraic statements relating two variables. 相似文献
76.
《Mathematical Methods in the Applied Sciences》2018,41(10):3684-3695
The paper formulates effective and nonimprovable stability conditions for a linear difference system involving 2 integer delays. The used technique combines algorithm of the discrete D‐decomposition method with some procedures of the polynomial theory. Contrary to the related existing results, the derived conditions are fully explicit with respect to both delays, which enables their simple applicability in various scientific and engineering areas. As an illustration, we show their importance in delayed feedback controls of discrete dynamical systems, with a particular emphasis put on stabilization of unstable steady states of the discrete logistic map. 相似文献
77.
78.
79.
Chun-Gang Ji 《Discrete Mathematics》2008,308(23):5860-5863
Let a(k,n) be the k-th coefficient of the n-th cyclotomic polynomials. In 1987, J. Suzuki proved that . In this paper, we improve this result and prove that for any prime p and any integer l≥1, we have
{a(k,pln)∣n,k∈N}=Z. 相似文献
80.
We consider orthogonal polynomials , where n is the degree of the polynomial and N is a discrete parameter. These polynomials are orthogonal with respect to a varying weight WN which depends on the parameter N and they satisfy a recurrence relation with varying recurrence coefficients which we assume to be varying monotonically as N tends to infinity. We establish the existence of the limit and link this limit to an external field for an equilibrium problem in logarithmic potential theory. 相似文献