全文获取类型
收费全文 | 869篇 |
免费 | 149篇 |
国内免费 | 121篇 |
专业分类
化学 | 28篇 |
晶体学 | 1篇 |
力学 | 70篇 |
综合类 | 27篇 |
数学 | 820篇 |
物理学 | 193篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 24篇 |
2019年 | 18篇 |
2018年 | 28篇 |
2017年 | 32篇 |
2016年 | 26篇 |
2015年 | 28篇 |
2014年 | 35篇 |
2013年 | 63篇 |
2012年 | 46篇 |
2011年 | 48篇 |
2010年 | 42篇 |
2009年 | 40篇 |
2008年 | 54篇 |
2007年 | 54篇 |
2006年 | 57篇 |
2005年 | 62篇 |
2004年 | 46篇 |
2003年 | 42篇 |
2002年 | 46篇 |
2001年 | 39篇 |
2000年 | 46篇 |
1999年 | 41篇 |
1998年 | 33篇 |
1997年 | 25篇 |
1996年 | 26篇 |
1995年 | 17篇 |
1994年 | 19篇 |
1993年 | 15篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有1139条查询结果,搜索用时 15 毫秒
41.
本文考虑以下2阶边值问题:其中.在关于A,B;P,Q,f的一定条件下,证明了以上问题存在分歧点.所用的主要工具是Krasnoselskii的局部分歧定理与KreinRutman定理. 相似文献
42.
Tsugunori Nogura 《Topology and its Applications》1983,15(1):65-69
We study the question whether a topological space X with a property can be embedded in a countably compact space X? with the same property . 相似文献
43.
Zbigniew J. Jurek 《Journal of multivariate analysis》1983,13(4):578-604
Let
= {Ut: t > 0} be a strongly continuous one-parameter group of operators on a Banach space X and Q be any subset of a set
(X) of all probability measures on X. By
(Q;
) we denote the class of all limit measures of {Utn(μ1 * μ2*…*μn)*δxn}, where {μn}Q, {xn}X and measures Utnμj (j=1, 2,…, n; N=1, 2,…) form an infinitesimal triangular array. We define classes Lm(
) as follows: L0(
)=
(
(X);
), Lm(
)=
(Lm−1(
);
) for m=1, 2,… and L∞(
)=m=0∞Lm(
). These classes are analogous to those defined earlier by Urbanik on the real line. Probability distributions from Lm(
), m=0, 1, 2,…, ∞, are described in terms of their characteristic functionals and their generalized Poisson exponents and Gaussian covariance operators. 相似文献
44.
A proper subgroup H of a group G is said to be strongly embedded if 2 (H) and 2(HH
g) (for all
). An involution i of G is said to be finite if
(for all g G). As is known, the structure of a (locally) finite group possessing a strongly embedded subgroup is determined by the theorems of Burnside and Brauer--Suzuki, provided that the Sylow 2-subgroup contains a unique involution. In this paper, sufficient conditions for the equality m
2(G)= 1 are established, and two analogs of the Burnside and Brauer—Suzuki theorems for infinite groups G possessing a strongly embedded subgroup and a finite involution are given. 相似文献
45.
An upper bound on the Ramsey number r(K2,n‐s,K2,n) where s ≥ 2 is presented. Considering certain r(K2,n‐s,K2,n)‐colorings obtained from strongly regular graphs, we additionally prove that this bound matches the exact value of r(K2,n‐s,K2,n) in infinitely many cases if holds. Moreover, the asymptotic behavior of r(K2,m,K2,n) is studied for n being sufficiently large depending on m. We conclude with a table of all known Ramsey numbers r(K2,m,K2,n) where m,n ≤ 10. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 252–268, 2003 相似文献
46.
Akira Hiraki 《Journal of Algebraic Combinatorics》2001,14(2):127-131
Let be a distance-regular graph of diameter d, valency k and r := maxi | (c
i,b
i) = (c
1,b
1). Let q be an integer with r + 1 q d – 1.In this paper we prove the following results:
Theorem 1
Suppose for any pair of vertices at distance q there exists a strongly closed subgraph of diameter q containing them. Then for any integer i with 1 i q
and for any pair of vertices at distance i there exists a strongly closed subgraph of diameter i containing them.
Theorem 2
If r 2, then
c
2r+3 1.As a corollary of Theorem 2 we have d k
2(r + 1) if r 2. 相似文献
47.
In this paper k-sets of type (a, b) with respect to hyperplanes are constructed in finite projective spaces using powers of Singer cycles. These are then used to construct further examples of sets of type (a, b) using various disjoint sets. The parameters of the associated strongly regular graphs are also calculated. The construction technique is then related to work of Foulser and Kallaher classifying rank three subgroups of AL(1, p
R). It is shown that the sets of type (a, b) arising from the Foulser and Kallaher construction in the case of projective spaces are isomorphic to some of those constructed in the present paper. 相似文献
48.
We call a sequence (T
n
) of measure preserving transformations strongly mixing if
tends to P(A)P(B) for arbitrary measurable A, B. We investigate whether one can pass to a suitable subsequence
such that
almost surely for all (or "many") integrable f. 相似文献
49.
A nonlinear integral operator T of the form (Tf)(s)=∫G K(t, f (σ(s, t))) dμ(t), for sG, is defined and investigated in the measure space (G, Σ, μ), where f and K are vector-valued functions with values in normed linear spaces E and F, respectively. The results are applied to the case of integro-differential operators in generalized Orlicz–Sobolev spaces. There are studied problems of existence, embeddings, and approximation by means of T. 相似文献
50.
We investigate BIBDs with three intersection numbers,x, y, and z, such that the relation on the block set given byA B iff the cardinality of the intersectionof A and B is not equal to x is an equivalence relation. Withsuch a design, we associate a family of strongly regular graphswith the same parameters. Two constructions producing infinitefamilies of such designs are given. 相似文献