全文获取类型
收费全文 | 1146篇 |
免费 | 28篇 |
国内免费 | 60篇 |
专业分类
化学 | 30篇 |
力学 | 27篇 |
综合类 | 2篇 |
数学 | 1078篇 |
物理学 | 97篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 20篇 |
2021年 | 18篇 |
2020年 | 25篇 |
2019年 | 28篇 |
2018年 | 21篇 |
2017年 | 20篇 |
2016年 | 19篇 |
2015年 | 21篇 |
2014年 | 49篇 |
2013年 | 159篇 |
2012年 | 35篇 |
2011年 | 60篇 |
2010年 | 47篇 |
2009年 | 101篇 |
2008年 | 95篇 |
2007年 | 77篇 |
2006年 | 66篇 |
2005年 | 39篇 |
2004年 | 38篇 |
2003年 | 33篇 |
2002年 | 24篇 |
2001年 | 25篇 |
2000年 | 24篇 |
1999年 | 22篇 |
1998年 | 30篇 |
1997年 | 28篇 |
1996年 | 22篇 |
1995年 | 19篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1234条查询结果,搜索用时 140 毫秒
91.
In this paper, the authors proved that finding all solutions of a given multivariate polynomial system is equivalent to solving a relative joint eigenvalue problem(Theorem 1) and in some cases one can find all solutions of the given system from the eigenvalues and vectors of one matrix or matrix pencil (Theorem 2). Especially the situation that the ideal generated by the given system is 0-dimensional is discussed. 相似文献
92.
Let f∈C[0,1],and Bn(f,x) be the a-th Bernstein polynomial associated with function f.ln 1967,the limit of iterates for B.(f,x) was given by Kelisky and Rivlin.After this,Many mathematicians studied and generalized this result.But anyway,all these discussions are only for univariate case ,In this paper,the main contrlbution is that the limit of lterates for Bernstein polynomial defined on a triangle is given completely. 相似文献
93.
94.
D.G. Meredith 《Journal of Mathematical Analysis and Applications》2003,282(2):732-743
A solution to an inverse problem involving noncharacteristic Cauchy conditions for a one-dimensional parabolic partial differential equation is presented which extends previous work in which the effects of a first-order convective term were ignored. The new solution involves a series expansion in Laguerre polynomials in time with spatial coefficients expressed in terms of a new set of special functions. These special functions are studied and many new properties are derived including a set of five term recurrence relations. The paper concludes with a theoretical study of conditions under which the inverse problem is well-posed. 相似文献
95.
Alfredo Peris 《Journal of Mathematical Analysis and Applications》2003,287(2):487-493
We show the existence of chaotic (in the sense of Devaney) polynomials on Banach spaces of q-summable sequences. Such polynomials P consist of composition of the backward shift with a certain fixed polynomial p of one complex variable on each coordinate. In general we also prove that P is chaotic in the sense of Auslander and Yorke if and only if 0 belongs to the Julia set of p. 相似文献
96.
Chen Huanyin 《东北数学》1997,(2)
PolynomialRingsoverNon┐noetherianPowerSeriesRingsChenHuanyin(陈焕艮)(DepartmentofMathematics,HunanNormalUniversity,Changsha,4100... 相似文献
97.
Regularity properties of Laguerre means are studied in terms of certain Sobolev spaces defined using Laguerre functions. As
an application we prove a localization theorem for Laguerre expansions. 相似文献
98.
In this paper, we present an efficient implementation of theO(mn + n
2 logn) time algorithm originally proposed by Nagamochi and Ibaraki (1992) for computing the minimum capacity cut of an undirected network. To enhance computation, various ideas are added so that it can contract as many edges as possible in each iteration. To evaluate the performance of the resulting implementation, we conducted extensive computational experiments, and compared the results with that of Padberg and Rinaldi's algorithm (1990), which is currently known as one of the practically fastest programs for this problem. The results indicate that our program is considerably faster than Padberg and Rinaldi's program, and its running time is not significantly affected by the types of the networks being solved.Corresponding author. 相似文献
99.
We introduce a notion of relative efficiency for axiom systems. Given an axiom system Aβ for a theory T consistent with S12, we show that the problem of deciding whether an axiom system Aα for the same theory is more efficient than Aβ is II2-hard. Several possibilities of speed-up of proofs are examined in relation to pairs of axiom systems Aα, Aβ, with Aα ? Aβ, both in the case of Aα, Aβ having the same language, and in the case of the language of Aα extending that of Aβ: in the latter case, letting Prα, Prβ denote the theories axiomatized by Aα, Aβ, respectively, and assuming Prα to be a conservative extension of Prβ, we show that if Aα — Aβ contains no nonlogical axioms, then Aα can only be a linear speed-up of Aβ; otherwise, given any recursive function g and any Aβ, there exists a finite extension Aα of Aβ such that Aα is a speed-up of Aβ with respect to g. Mathematics Subject Classification: 03F20, 03F30. 相似文献
100.
Kate Copestake 《Mathematical Logic Quarterly》1997,43(3):287-310
Enumeration reducibility is a notion of relative computability between sets of natural numbers where only positive information about the sets is used or produced. Extending e-reducibility to partial functions characterises relative computability between partial functions. We define a polynomial time enumeration reducibility that retains the character of enumeration reducibility and show that it is equivalent to conjunctive non-deterministic polynomial time reducibility. We define the polynomial time e-degrees as the equivalence classes under this reducibility and investigate their structure on the recursive sets, showing in particular that the pe-degrees of the computable sets are dense and do not form a lattice, but that minimal pairs exist. We define a jump operator and use it to produce a characterisation of the polynomial hierarchy. 相似文献