全文获取类型
收费全文 | 126篇 |
免费 | 1篇 |
国内免费 | 3篇 |
专业分类
化学 | 56篇 |
力学 | 8篇 |
数学 | 58篇 |
物理学 | 8篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 3篇 |
2012年 | 2篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 19篇 |
2007年 | 5篇 |
2006年 | 10篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有130条查询结果,搜索用时 31 毫秒
1.
It is proved that biorthogonal polynomials obey two different kinds of Christoffel-Darboux-type formulae, one linking polynomials with a different parameter and one combining polynomials with different degrees. This is used to produce a mixed recurrence relation, which is valid for all biorthogonal polynomials. This recurrence relation establishes several results on interlacing property of zeros of successive biorthogonal polynomials and leads to a new result on the interlace of zeros of orthogonal polynomials (of equal degrees) with respect to two distributionsdψ(x) andx p dψ(x), 0<p≤1, with support in either [0, 1] or [1, ∞). 相似文献
2.
We study a leader follower game with two players: a terrorist and a state where the later one installs facilities that provide support in case of a terrorist attack. While the Terrorist attacks one of the metropolitan areas to maximize his utility, the State, which acts as a leader, installs the facilities such that the metropolitan area attacked is the one that minimizes her disutility (i.e., minimizes ‘loss’). We solve the problem efficiently for one facility and we formulate it as a mathematical programming problem for a general number of facilities. We demonstrate the problem via a case study of the 20 largest metropolitan areas in the United States. 相似文献
3.
CONVERSION OF LIGHT ENERGY TO ELECTROSTATIC ENERGY IN THE PROTON PUMP OF HALOBACTERIUM HALOBIUM 总被引:10,自引:0,他引:10
Abstract— The energetics of the proton pump in Halobacterium halobium is considered on a molecular level. It is proposed that absorption of light by bacteriorhodopsin leads to charge separation and sequential changes in the proton affinities some of the protein groups resulting in proton pumping against the pH gradient. Two alternative models of 'through-space' and 'through-bond' charge separation are proposed. Novel diagrams that describe the energetics of the pumping process are presented. These diagrams can be used both to examine different models of bacteriorhodopsin and for considering other photobiological processes that involve conversion of light energy to electrostatic energy. 相似文献
4.
We investigate asymptotic behaviour of solutions of the functional-differentialequation
where f and g arelocally Lipschitz functions, C is a continuous matrix and thesmooth lag function obeys 0 (t) t for t 0. We transformthe equation into a delay equation with an infinity of delaysand use a theorem of Söderlind to derive sufficient conditionsfor stability and for asymptotic stability in the case limt (t) = . The situation is qualitatively different when limt (t) = * < and we outline stability conditions for thatcase by employing direct techniques. 相似文献
5.
The solubilities of methane, ethane, propane, and n-butane were measured in aqueous solutions of sodium dodecylsulfate (NaDS) (0–0.1M) from 15 to 27°C. From these measurements the standard Gibbs energies, entropies, and enthalpies for the process of transferring the solute molecules from the gaseous phase into the solutions were calculated. An approximate relationship was found relating the volume fraction of the micelles to NaDS concentration. 相似文献
6.
Jeffry D. Madura Yasushi Nakajima Rodney M. Hamilton Andrzej Wierzbicki Arieh Warshel 《Structural chemistry》1996,7(2):131-138
The interactions between biologically important enzymes and drugs are of great interest. In order to address some aspects of these interactions we have initiated a program to investigate enzymedrug interactions. Specifically, the interactions between one of the isozymes of carbonic anhydrase and a family of drugs known as sulfonamides have been studied using computational methods. In particular the electrostatic free energy of binding of carbonic anhydrase II with acetazolamide, methazolamide,p-chlorobenzenesulfonamide,p-aminobenzenesulfonamide and three new compounds (MK1, MK2, and MK3) has been computed using finite-difference Poisson-Boltzmann (FDPB) [1] method and the semimacroscopic version [2, 3] of the protein dipole Langevin dipole (PDLD) method [4]. Both methods, FDPB and PDLD, give similar results for the electrostatic free energy of binding even though different charges and different treatments were used for the protein. The calculated electrostatic binding free energies are in reasonable agreement with the experimental data. The potential and the limitation of electrostatic models for studies of binding energies are discussed. 相似文献
7.
8.
We address the evaluation of highly oscillatory integrals,with power-law and logarithmic singularities.Such problems arise in numerical methods in engineering.Notably,the evaluation of oscillatory integrals dominates the run-time for wave-enriched boundary integral formulations for wave scattering,and many of these exhibit singularities.We show that the asymptotic behaviour of the integral depends on the integrand and its derivatives at the singular point of the integrand,the stationary points and the endpoints of the integral.A truncated asymptotic expansion achieves an error that decays faster for increasing frequency.Based on the asymptotic analysis,a Filon-type method is constructed to approximate the integral.Unlike an asymptotic expansion,the Filon method achieves high accuracy for both small and large frequency.Complex-valued quadrature involves interpolation at the zeros of polynomials orthogonal to a complex weight function.Numerical results indicate that the complex-valued Gaussian quadrature achieves the highest accuracy when the three methods are compared.However,while it achieves higher accuracy for the same number of function evaluations,it requires signi cant additional cost of computation of orthogonal polynomials and their zeros. 相似文献
9.
The question of A-acceptability in regard to derivatives of Rm/n, the [m/n] Padé approximation to the exponential, is examined for a range of values of m and n. It is proven that R′n − 1/n, R′n/n, R′n + 1/nand R″n/n are A-acceptable and that numerous other choices of m and n lead to non-A-acceptability. The results seem to indicate that the A-acceptability pattern of Rm/n(k) displays an intriguing generalization of the Wanner-Hairer-Nørsett theorem on the A-acceptability of Rm/n. 相似文献
10.
We show that in a contest with a single prize, the expected effort made by the kth highest valuation participant bounds the sum of the expected efforts made by all of the participants with valuations less than the kth highest valuations. We also show that in the limit case of a contest with m prizes, the expected effort made by the kth highest valuation participant when the bidders are risk-neutral is greater than the expected effort in the risk-averse case. 相似文献