全文获取类型
收费全文 | 51篇 |
免费 | 3篇 |
国内免费 | 3篇 |
专业分类
化学 | 17篇 |
数学 | 35篇 |
物理学 | 5篇 |
出版年
2022年 | 1篇 |
2018年 | 1篇 |
2016年 | 1篇 |
2014年 | 4篇 |
2013年 | 1篇 |
2012年 | 1篇 |
2011年 | 3篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2002年 | 1篇 |
2000年 | 5篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有57条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Melvyn B. Nathanson 《Monatshefte für Mathematik》1980,89(3):219-222
Let
. LetG
m
(R) be the graph whose vertices are the numbers 1, 2, ...,m and whose edges are all pairs {a, b} such thata+br (modm) for somerR. LetC
m
(R) be the number of connected components ofG
m
(R). Letd be the greatest common divisor ofm and the differencesr
j
–r
j
or allr
i
,r
j
R. ThenC
m
(R) is equal to (i) (d+1)/2 ifd is odd, (ii)d/2 ifd is even andr is odd for allrR, or (iii) (d/2)+1 ifd is even andr is even for allrR.This research was supported in part by the National Science Foundation under grant No. MCS78-07908. 相似文献
5.
Lawrence JR Glass SV Park SC Nathanson GM 《The journal of physical chemistry. A》2005,109(33):7458-7465
The entry of HCl into 60-68 wt % D(2)SO(4) and HBr into 68 wt % acid containing 0-0.18 M 1-butanol was monitored by measuring the fractions of impinging HCl and HBr molecules that desorb as DCl and DBr after undergoing H --> D exchange within the deuterated acid. The addition of 0.18 M butanol to the acid creates butyl films that reach approximately 80% surface coverage at 213 K. Surprisingly, this butyl film does not impede exchange but instead enhances it: the HCl --> DCl exchange fractions increase from 0.52 to 0.74 for 60 wt % D(2)SO(4) and from 0.14 to 0.27 for 68 wt % D(2)SO(4). HBr --> DBr exchange increases even more sharply, rising from 0.22 to 0.65 for 68 wt % D(2)SO(4). We demonstrate that this enhanced exchange corresponds to enhanced uptake into the butyl-coated acid for HBr and infer this equivalence for HCl. In contrast, the entry probability of the basic molecule CF(3)CH(2)OH exceeds 0.85 at all acid concentrations and is only slightly diminished by the butyl film. The OD groups of surface butanol molecules may assist entry by providing extra interfacial protonation sites for HCl and HBr dissociation. The experiments suggest that short-chain surfactants in sulfuric acid aerosols do not hinder heterogeneous reactions of HCl or HBr with other solute species. 相似文献
6.
7.
Weston I. Nathanson 《Journal of Optimization Theory and Applications》1971,8(4):256-270
Necessary conditions are obtained for the general control problem with the minimizing are required to pass through intermediate-constraint manifolds. It is shown that this includes cases where the integrand or the region of admissibility changes at the constraint points.This research was partly sponsored by the Office of Naval Research under contract NONR-233(76). 相似文献
8.
Melvyn B Nathanson 《Journal of Combinatorial Theory, Series A》1977,22(1):61-68
Let f: I → I be a continuous function on a closed interval I. If there exists x?I which has period 3 with respect to f, then Li and Yorke [1] proved that f is chaotic in the sense that there are not only points x?I of arbitrarily large period, but also uncountably many points x?I which are not even asymptotically periodic with respect to f. By using only elementary combinatorial facts about permutations, it is shown that if there is a point x?I of period p with respect to f, where p is divisible by 3, 5, or 7, then f is chaotic. The proof is followed by a study of some related combinatorial problems in symmetric groups. 相似文献
9.
M. B. Nathanson 《Acta Mathematica Hungarica》2016,149(1):233-237
If P is a lattice polytope (that is, the convex hull of a finite set of lattice points in \({\mathbf{R}^n}\)), then every sum of h lattice points in P is a lattice point in the h-fold sumset hP. However, a lattice point in the h-fold sumset hP is not necessarily the sum of h lattice points in P. It is proved that if the polytope P is a union of unimodular simplices, then every lattice point in the h-fold sumset hP is the sum of h lattice points in P. 相似文献
10.
Using a new graphical representation for partitions, the author obtains a family of partition identities associated with partitions into distinct parts of an arithmetic progression, or, more generally, with partitions into distinct parts of a set that is a finite union of arithmetic progressions associated with a modular sum-free Sidon set. Partition identities are also constructed for sets associated with modular sum-free sets. 相似文献