全文获取类型
收费全文 | 1062篇 |
免费 | 51篇 |
国内免费 | 36篇 |
专业分类
化学 | 7篇 |
晶体学 | 3篇 |
力学 | 6篇 |
综合类 | 29篇 |
数学 | 884篇 |
物理学 | 220篇 |
出版年
2024年 | 2篇 |
2023年 | 35篇 |
2022年 | 53篇 |
2021年 | 52篇 |
2020年 | 48篇 |
2019年 | 27篇 |
2018年 | 19篇 |
2017年 | 26篇 |
2016年 | 32篇 |
2015年 | 19篇 |
2014年 | 39篇 |
2013年 | 45篇 |
2012年 | 15篇 |
2011年 | 32篇 |
2010年 | 23篇 |
2009年 | 72篇 |
2008年 | 79篇 |
2007年 | 62篇 |
2006年 | 68篇 |
2005年 | 31篇 |
2004年 | 35篇 |
2003年 | 38篇 |
2002年 | 61篇 |
2001年 | 42篇 |
2000年 | 35篇 |
1999年 | 57篇 |
1998年 | 36篇 |
1997年 | 27篇 |
1996年 | 16篇 |
1995年 | 5篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1149条查询结果,搜索用时 16 毫秒
951.
《Discrete Mathematics》2019,342(7):1989-2001
Quantum maximum-distance-separable (MDS) codes are an important class of quantum codes. In this paper we mainly use classical Hermitian self-orthogonal generalized Reed–Solomon codes to construct three classes of new quantum MDS codes. Further, these quantum MDS codes have large minimum distance and short length. 相似文献
952.
Koji Chinen 《Discrete Mathematics》2019,342(12):111601
In this paper, first we formulate the notion of divisible formal weight enumerators and propose an algorithm for the efficient search of the formal weight enumerators divisible by two. The main tools are the binomial moments. It leads to the discovery of several new families of formal weight enumerators. Then, as a result, we find examples of extremal formal weight enumerators which do not satisfy the Riemann hypothesis. 相似文献
953.
In this paper we initiate the study of cyclic algebraic geometry codes. We give conditions to construct cyclic algebraic geometry codes in the context of algebraic function fields over a finite field by using their group of automorphisms. We prove that cyclic algebraic geometry codes constructed in this way are closely related to cyclic extensions. We also give a detailed study of the monomial equivalence of cyclic algebraic geometry codes constructed with our method in the case of a rational function field. 相似文献
954.
《Discrete Mathematics》2022,345(11):113037
We show that no more new distance-regular graphs in the tables of the book of (Brouwer, Cohen, Neumaier, 1989) can be produced by using the coset graph of additive completely regular codes over finite fields. 相似文献
955.
For a linear code over GF(q) we consider two kinds of “subcodes” called residuals and punctures. When does the collection of residuals or punctures determine the isomorphism class of the code? We call such a code residually or puncture reconstructible. We investigate these notions of reconstruction and show that, for instance, selfdual binary codes are puncture and residually reconstructible. A result akin to the edge reconstruction of graphs with sufficiently many edges shows that a code whose dimension is small in relation to its length is puncture reconstructible. © 1998 John Wiley & Sons, Inc. J Combin Designs 6: 285–291, 1998 相似文献
956.
We address the problem of encoding entanglement-assisted (EA) quantum error-correcting codes (QECCs) and of the corresponding complexity. We present an iterative algorithm from which a quantum circuit composed of CNOT, H, and S gates can be derived directly with complexity O(n2) to encode the qubits being sent. Moreover, we derive the number of each gate consumed in our algorithm according to which we can design EA QECCs with low encoding complexity. Another advantage brought by our algorithm is the easiness and efficiency of programming on classical computers. 相似文献
957.
T. Aaron Gulliver Masaaki Harada Takuji Nishimura Patric R. J. Östergård 《Designs, Codes and Cryptography》2005,37(3):465-471
The weight enumerator of a formally self-dual even code is obtained by the Gleason theorem. Recently, Kim and Pless gave some
restrictions on the possible weight enumerators of near-extremal formally self-dual even codes of length divisible by eight.
In this paper, the weight enumerators for which there is a near-extremal formally self-dual even code are completely determined
for lengths 24 and 32, by constructing new near-extremal formally self-dual codes. We also give a classification of near-
extremal double circulant codes of lengths 24 and 32.
Communicated by: P. Fitzpatrick 相似文献
958.
Let G: = G(1,n,q) denote the Grassmannian of lines in PG(n,q), embedded as a point-set in PG(N, q) with
For n = 2 or 3 the characteristic function
of the complement of G is contained in the linear code generated by characteristic functions of complements of n-flats in PG(N, q). In this paper we prove this to be true for all cases (n, q) with q = 2 and we conjecture this to be true for all remaining cases (n, q). We show that the exact polynomial degree of
is
for δ: = δ(n, q) = 0 or 1, and that the possibility δ = 1 is ruled out if the above conjecture is true. The result deg(
for the binary cases (n,2) can be used to construct quantum codes by intersecting G with subspaces of dimension at least
相似文献
959.
利用有限域上对合阵构作认证码 总被引:1,自引:0,他引:1
本文利用有限域上n阶对合阵给同了构作Cartesion认证码的一种新方案,计算了这类认证码的参数,在编码规则等概率分布选取的假设下,给出了这类认证码被被成功地模仿攻击的最大概率P1和被成功地替换攻击的最大概率Ps 相似文献
960.