全文获取类型
收费全文 | 1215篇 |
免费 | 112篇 |
国内免费 | 177篇 |
专业分类
化学 | 100篇 |
晶体学 | 2篇 |
力学 | 11篇 |
综合类 | 22篇 |
数学 | 1071篇 |
物理学 | 298篇 |
出版年
2023年 | 16篇 |
2022年 | 28篇 |
2021年 | 26篇 |
2020年 | 36篇 |
2019年 | 34篇 |
2018年 | 33篇 |
2017年 | 35篇 |
2016年 | 42篇 |
2015年 | 34篇 |
2014年 | 70篇 |
2013年 | 79篇 |
2012年 | 61篇 |
2011年 | 74篇 |
2010年 | 60篇 |
2009年 | 76篇 |
2008年 | 88篇 |
2007年 | 86篇 |
2006年 | 78篇 |
2005年 | 65篇 |
2004年 | 58篇 |
2003年 | 58篇 |
2002年 | 60篇 |
2001年 | 43篇 |
2000年 | 45篇 |
1999年 | 46篇 |
1998年 | 38篇 |
1997年 | 21篇 |
1996年 | 24篇 |
1995年 | 9篇 |
1994年 | 12篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1969年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有1504条查询结果,搜索用时 328 毫秒
991.
In this article, a new characterization of the closedness of the sum of two closed subspaces of a Hilbert space is established. 相似文献
992.
In this paper we introduce the concept of tensor sum semigroups. Also we have given the examples of tensor sum operators which induce dynamical system on weighted locally convex function spaces. 相似文献
993.
994.
Gillian Hatch 《International Journal of Mathematical Education in Science & Technology》2013,44(5):721-726
This article considers a family of divisibility tests for low-valued primes and their place as activities which develop the use of proof both within school and in teacher training. The way in which these tests can be seen as developing one from another is seen as of value in encouraging students to produce their own proofs. 相似文献
995.
996.
We systematically investigate the mass spectra of {Qs}{Q(')s} molecular states in the framework of QCD sum rules. The interpolating currents representing the molecular states are proposed. Technically, contributions of the operators up to dimension six are included in operator product expansion (OPE). The masses for molecular states with various {Qs}{Q(')s} configurations are presented. The result 4.36 ± 0.08 Ge V for theDs* Ds0- * molecular state is consistent with the mass 4350+4.6 -5.1± 0.7 MeV of the newly observed X(4350), which could support X(4350) interpreted as a D*D*so molecular state. 相似文献
997.
We first introduce the multiple Dedekind–Rademacher sum with a parameter in finite fields and establish its reciprocity law. We then construct an analog of the higher-dimensional Apostol–Dedekind sums, and establish their reciprocity laws using the parameterized Dedekind sum. 相似文献
998.
The subset sum problem over finite fields is a well-known NP-complete problem. It arises naturally from decoding generalized Reed–Solomon codes. In this paper, we study the number of solutions of the subset sum problem from a mathematical point of view. In several interesting cases, we obtain explicit or asymptotic formulas for the solution number. As a consequence, we obtain some results on the decoding problem of Reed–Solomon codes. 相似文献
999.
In this paper,we investigate not only the acceleration problem of the q-Bernstein polynomials Bn(f,q;x)to B∞(f,q;x)but also the convergence of their iterated Boolean sum.Using the methods of exact estimate and theories of modulus of smoothness,we get the respective estimates of the convergence rate,which suggest that q-Bernstein polynomials have the similar answer with the classical Bernstein polynomials to these two problems. 相似文献
1000.
We apply relations of n-dimensional Kloosterman sums to exponential sums over finite fields to count the number of low-weight codewords in a cyclic code with two zeros. As a corollary we obtain a new proof for a result of Carlitz which relates one- and two-dimensional Kloosterman sums. In addition, we count some power sums of Kloosterman sums over certain subfields. 相似文献