全文获取类型
收费全文 | 2986篇 |
免费 | 237篇 |
国内免费 | 378篇 |
专业分类
化学 | 126篇 |
晶体学 | 2篇 |
力学 | 60篇 |
综合类 | 48篇 |
数学 | 2783篇 |
物理学 | 582篇 |
出版年
2024年 | 4篇 |
2023年 | 43篇 |
2022年 | 60篇 |
2021年 | 64篇 |
2020年 | 79篇 |
2019年 | 85篇 |
2018年 | 74篇 |
2017年 | 82篇 |
2016年 | 93篇 |
2015年 | 92篇 |
2014年 | 151篇 |
2013年 | 183篇 |
2012年 | 140篇 |
2011年 | 153篇 |
2010年 | 130篇 |
2009年 | 186篇 |
2008年 | 249篇 |
2007年 | 200篇 |
2006年 | 182篇 |
2005年 | 165篇 |
2004年 | 123篇 |
2003年 | 145篇 |
2002年 | 140篇 |
2001年 | 92篇 |
2000年 | 115篇 |
1999年 | 99篇 |
1998年 | 89篇 |
1997年 | 69篇 |
1996年 | 67篇 |
1995年 | 31篇 |
1994年 | 38篇 |
1993年 | 26篇 |
1992年 | 16篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 13篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1936年 | 4篇 |
排序方式: 共有3601条查询结果,搜索用时 0 毫秒
61.
ZHANG YongBing 《中国科学A辑(英文版)》2009,(8)
We use the contact Yamabe flow to find solutions of the contact Yamabe problem on K-contact manifolds. 相似文献
62.
In this paper, we study the weighted Korn inequality on some irregular domains, e.g., s-John domains and domains satisfying quasihyperbolic boundary conditions. Examples regarding sharpness of the Korn inequality on these domains are presented. Moreover, we show that Korn inequalities imply certain Poincaré inequality. 相似文献
63.
65.
In this note we consider the Schrödinger equation on compact manifolds equipped with possibly degenerate metrics. We prove Strichartz estimates with a loss of derivatives. The rate of loss of derivatives depends on the degeneracy of metrics. For the non-degenerate case we obtain, as an application of the main result, the same Strichartz estimates as that in the elliptic case. This extends Strichartz estimates for Riemannian metrics proved by Burq-Gérard-Tzvetkov to the non-elliptic case and improves the result by Salort for the degenerate case. We also investigate the optimality of the result for the case on 𝕊3 × 𝕊3. 相似文献
66.
NA序列部分和的矩完全收敛性 总被引:4,自引:0,他引:4
讨论了NA序列部分和的矩完全收敛性,在一定条件下获得了NA序列矩完全收敛的充要条件,显示了矩完全收敛和矩条件之间的关系,将独立同分布随机变量序列矩完全收敛的结果推广到NA序列,得到了与独立随机变量序列情形类似的结果. 相似文献
67.
In this work we study the semileptonic decay of ${\bar{B}}_{s}^{0}\to \phi {l}^{+}{l}^{-}$ (l=e, μ, τ) with the QCD sum rule method. We calculate the ${\bar{B}}_{s}^{0}\to \phi $ translation form factors relevant to this semileptonic decay, then the branching ratios of ${\bar{B}}_{s}^{0}\to \phi {l}^{+}{l}^{-}$ (l=e, μ, τ) decays are calculated with the form factors obtained here. Our result for the branching ratio of ${\bar{B}}_{s}^{0}\to \phi {\mu }^{+}{\mu }^{-}$ agree very well with the recent experimental data. For the unmeasured decay modes such as ${\bar{B}}_{s}^{0}\to \phi {e}^{+}{e}^{-}$ and ${\bar{B}}_{s}^{0}\to \phi {\tau }^{+}{\tau }^{-}$ , we give theoretical predictions. 相似文献
68.
Ping Zhang 《Entropy (Basel, Switzerland)》2022,24(2)
Shinagawa and Iwata are considered quantum security for the sum of Even–Mansour (SoEM) construction and provided quantum key recovery attacks by Simon’s algorithm and Grover’s algorithm. Furthermore, quantum key recovery attacks are also presented for natural generalizations of SoEM. For some variants of SoEM, they found that their quantum attacks are not obvious and left it as an open problem to discuss the security of such constructions. This paper focuses on this open problem and presents a positive response. We provide quantum key recovery attacks against such constructions by quantum algorithms. For natural generalizations of SoEM with linear key schedules, we also present similar quantum key recovery attacks by quantum algorithms (Simon’s algorithm, Grover’s algorithm, and Grover-meet-Simon algorithm). 相似文献
69.
Let (X, d, μ) be a metric measure space with non-negative Ricci curvature. This paper is concerned with the boundary behavior of harmonic function on the (open) upper half-space . We derive that a function f of bounded mean oscillation (BMO) is the trace of harmonic function on , whenever u satisfies the following Carleson measure condition where denotes the total gradient and denotes the (open) ball centered at with radius . Conversely, the above condition characterizes all the harmonic functions whose traces are in BMO space. 相似文献
70.
广义度量空间理论是一般拓扑学研究的重要课题。本文综述了90年代广义度量空间理论的成就,分析了它的主要研究课题,所取得的重要结果是国内学者在该方向的贡献。 相似文献