全文获取类型
收费全文 | 300篇 |
免费 | 100篇 |
国内免费 | 9篇 |
专业分类
化学 | 71篇 |
力学 | 9篇 |
综合类 | 27篇 |
数学 | 198篇 |
物理学 | 104篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 15篇 |
2021年 | 16篇 |
2020年 | 29篇 |
2019年 | 16篇 |
2018年 | 19篇 |
2017年 | 20篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 27篇 |
2013年 | 29篇 |
2012年 | 29篇 |
2011年 | 22篇 |
2010年 | 18篇 |
2009年 | 10篇 |
2008年 | 18篇 |
2007年 | 18篇 |
2006年 | 14篇 |
2005年 | 12篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
排序方式: 共有409条查询结果,搜索用时 78 毫秒
51.
In this paper a two-stage game that involves three container terminals located in Karachi Port in Pakistan is discussed. In the first stage, the three terminals have to decide on whether to act as a singleton or to enter into a coalition with one or both of the other terminals. The decision at this stage should presumably be based on the predicted outcome for the second stage. The second stage is here modelled as a Bertrand game with one outside competitor, the coalition and the terminal in Karachi Port (if any) that has not joined the coalition. Furthermore, three partial and one grand coalition among the three terminals at Karachi Port are investigated. The concepts of “characteristic function” and “core” are used to analyse the stability of these coalitions and this revealed that one combination does not satisfy the superadditivity property of the characteristic function and can therefore be ruled out. The resulting payoffs (profits) of these coalitions are analysed on the basis of “core”. The best payoff for all players is in the case of a “grand coalition”. However, the real winner is the outsider (the terminal at the second port) which earns a better payoff without joining the coalition, and hence will play the role of the “orthogonal free-rider”. 相似文献
52.
在网站动态竞争模型的基础上,建立了含有真正的合作关系的网站竞争模型.随后对二维的特殊情况进行了定性分析,结合给出的数值模拟图,分析了模型中的相关系数对系统的作用,并针对分析的结果讨论了影响网站发展的主要因素. 相似文献
53.
54.
We propose a formal-behavioral framework with 3 components: nonselfish motives, expectations about others' nonselfish motives, and a game-theoretic component. For nonselfish motives, 3 nonstandard utility models representing altruism, inequality aversion, and norms are considered. Expectations are modeled as certain versus uncertain expectations. The game-theoretic component predicts behavior of actors and actors' expectations about behaviors of others. This framework is applied to asymmetric one-shot prisoner's dilemmas; predictions are tested experimentally. Formal analyses show that asymmetry provides new predictions through which nonstandard utility-expectation models can be distinguished. Empirical tests show that the inequality aversion model does considerably worse than altruistic and normative variants. Statistical tests for own motives, expected motives, and the association between the two are provided, while accounting for decision noise. 相似文献
55.
随着智能手机的普及和3G技术的发展,信息呈指数式增长,从海量的信息中提取出用户感兴趣的内容已成为电子商务发展的一个重要趋势,然而传统的推荐策略已不能满足用户的需求.为此,基于移动云计算和位置信息,提出了一个个性化服务推荐模型解决方案,该方案综合了社交网络和时效性,建立了用户兴趣模型库.基于这个解决方案,在Android平台上,实现了初步的个性化图片推荐模型,取得了不错的效果.个性化服务推荐系统具有良好的发展和应用前景,能有效的保留客户,提高电子商务系统的服务能力,带来巨大的效益,具有一定的理论和现实意义. 相似文献
56.
谢溪庄 《数学的实践与认识》2013,43(2)
考虑并研究了一类具有分布时滞和非局部空间效应影响的合作系统的反应扩散模型.利用Wang,Li和Ruan建立的非局部时滞反应扩散方程组波前解存在性的理论,证明了连接零平衡解和正平衡解的行波解的存在性. 相似文献
57.
58.
由Internet构成的复杂网络的动力学特性主要受到用户需求行为的影响,具备时域的统计规律性. 通过对区域群体用户需求行为的时域实验统计分析,发现用户对Web网站的访问频度及其生成的二分网络的入度分布也呈现幂律分布和集聚现象,其幂指数介于1.7到1.8之间. 建立了虚拟资源网络VRN和物理拓扑网络PTN双层模型,分析了双层模型映射机理,并对网络用户需求行为进行建模. 虚拟资源网络VRN对物理拓扑网络PTN映射过程的不同机理,模拟了Internet资源网络到物理网络的不同影响模式. 幂律分布的用户需求特性会
关键词:
复杂网络
无标度拓扑
用户需求
相变 相似文献
59.
Florian Molton 《Magnetic resonance in chemistry : MRC》2020,58(8):718-726
Solid-state continuous wave (cw) electronic paramagnetic resonance (EPR) spectroscopy is particularly suitable for metal complex analysis. Extracting magnetic parameters by simulation is often necessary to describe the electronic structure of the studied molecular compounds that can have various electronic spin states and characterized by different parameters like g-values, hyperfine coupling or zero field splitting values. Easyspin toolbox on MATLAB is a powerful tool, but for the user, it requires spending time with coding and could discourage nonexperts. Facing this context, we have developed a graphical user interface called Simultispin, dedicated to solid-state cw-EPR spectra simulation. Some examples of experimental spectra of metal complexes (mixture of low spin and high spin FeIII complexes, dynamic disorder of a CuII complex, photogeneration of a MnIII complex), highlighting specific solid-state functions, are described and analyzed based on simulations performed with Simultispin. We hope that its ergonomy and the ease to set up a complete set of parameters to get reliable simulations could help a large EPR community to improve the efficiency of their interpretations. 相似文献
60.