全文获取类型
收费全文 | 3696篇 |
免费 | 83篇 |
国内免费 | 124篇 |
专业分类
化学 | 711篇 |
晶体学 | 15篇 |
力学 | 5篇 |
综合类 | 4篇 |
数学 | 2964篇 |
物理学 | 204篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 27篇 |
2021年 | 20篇 |
2020年 | 24篇 |
2019年 | 65篇 |
2018年 | 71篇 |
2017年 | 36篇 |
2016年 | 43篇 |
2015年 | 38篇 |
2014年 | 86篇 |
2013年 | 210篇 |
2012年 | 87篇 |
2011年 | 209篇 |
2010年 | 220篇 |
2009年 | 264篇 |
2008年 | 346篇 |
2007年 | 338篇 |
2006年 | 296篇 |
2005年 | 195篇 |
2004年 | 197篇 |
2003年 | 162篇 |
2002年 | 108篇 |
2001年 | 84篇 |
2000年 | 94篇 |
1999年 | 111篇 |
1998年 | 99篇 |
1997年 | 51篇 |
1996年 | 74篇 |
1995年 | 70篇 |
1994年 | 69篇 |
1993年 | 52篇 |
1992年 | 29篇 |
1991年 | 13篇 |
1990年 | 22篇 |
1989年 | 11篇 |
1988年 | 15篇 |
1987年 | 9篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 10篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
排序方式: 共有3903条查询结果,搜索用时 18 毫秒
11.
We give a purely algebro-geometric proof of the fact that every nonsingular
projective curve can be defined over a finite extension of its moduli field.
This extends a result byWolfart [7] to curves over fields of arbitrary
characteristic.
Received: 30 November 2001 相似文献
12.
This paper deals with various problems in lattice theory involving local extrema. In particular, we construct infinite series of highly symmetric spherical 3-designs which include some of the examples constructed in [9] in dimensions 5 and 7. We also construct new types of dual-extreme lattices.Received June 29, 2002; in final form January 14, 2003
Published online May 16, 2003 相似文献
13.
We study the metrical theory of fibred systems, in particular, in the case of continued fraction mixing systems. We get the
limit distribution of the largest value of a continued fraction mixing stationary stochastic process with infinite expectation
and some related results. These are analogous to J. Galambos, W. Philipp, and H. G. Diamond–J. D. Vaaler theorems for the
regular continued fractions. As an application, we see that these theorems hold for Jacobi-Perron algorithm.
Received September 30, 2001; in revised form January 8, 2002 相似文献
14.
The conformal class of a Hermitian metric g on a compact almost complex manifold (M2m, J) consists entirely of metrics that are Hermitian with respect to J. For each one of these metrics, we may define a J-twisted
version of the Ricci curvature, the J-Ricci curvature, and its corresponding trace, the J-scalar curvature sJ. We ask if the conformal class of g carries a metric with constant sJ, an almost Hermitian version of the usual Yamabe problem posed for the scalar curvature s. We answer our question in the
affirmative. In fact, we show that (2m−1)sJ−s=2(2m−1)W(ω, ω), where W is the Weyl tensor and ω is the fundamental form of g. Using techniques developed for the solution
of the problem for s, we construct an almost Hermitian Yamabe functional and its corresponding conformal invariant. This invariant
is bounded from above by a constant that only depends on the dimension of M, and when it is strictly less than the universal
bound, the problem has a solution that minimizes the almost complex Yamabe functional. By the relation above, we see that
when W (ω, ω) is negative at least one point, or identically zero, our problem has a solution that minimizes the almost Hermitian
Yamabe functional, and the universal bound is reached only in the case of the standard 6-sphere
equipped with a suitable almost complex structure. When W(ω, ω) is non-negative and not identically zero, we prove that the
conformal invariant is strictly less than the universal bound, thus solving the problem for this type of manifolds as well.
We discuss some applications. 相似文献
15.
The authors prove that a proper monomial holomorphic mapping from the two-ball to the N-ball has degree at most 2N-3, and
that this result is sharp. The authors first show that certain group-invariant polynomials (related to Lucas polynomials)
achieve the bound. To establish the bound the authors introduce a graph-theoretic approach that requires determining the number
of sinks in a directed graph associated with the quotient polynomial. The proof also relies on a result of the first author
that expresses all proper polynomial holomorphic mappings between balls in terms of tensor products. 相似文献
16.
We define the index of composition λ(n) of an integer n ⩾ 2 as λ(n) = log n/log γ(n), where γ(n) stands for the product of the primes dividing n, and first establish that λ and 1/λ both have asymptotic mean value 1. We then establish that, given any ɛ > 0 and any integer
k ⩾ 2, there exist infinitely many positive integers n such that . Considering the distribution function F(z,x) := #{n < x : λ(n) > z}, we prove that, given 1 < z < 2 and ɛ > 0, then, if x is sufficiently large,
this last inequality also holding if z ⩾ 2. We then use these inequalities to obtain probabilistic results and we state a conjecture. Finally, using (*), we show
that the probability that the abc conjecture does not hold is 0.
Research supported in part by a grant from NSERC.
Re?u le 17 décembre 2001; en forme révisée le 23 mars 2002
Publié en ligne le 11 octobre 2002 相似文献
17.
Our purpose in the paper is to find the most general linear congruence relation of the Hardy-Williams type for linear combinations of special values of Kubota-Leopoldt 2-adic L-functions L2(k,χω1−k) with k running over any finite subset of not necessarily consisting of consecutive integers (see Acta Arith. 47 (1986) 263; Publ. Math. Fac. Sci. Besançon, Théorie des Nombres, 1995/1996; Publ. Math. Debrecen 56 (2000) 677 and cf. Mathematics and Its Applications, Vol. 511, Kluwer Academic Publishers, Dordrecht, Boston, London, 2000). If k runs over finite subsets of consisting of consecutive integers see Compositio Math. 111 (1998) 289; Publ. Math. Debrecen 56 (2000) 677; Hardy and Williams, 1986; Compositio Math. 75 (1990) 271; Acta Arith. 71 (1995) 273; 52 (1989) 147; J. Number Theory 34 (1990) 362. In order to obtain the most general congruences of this type we make use of divisibility properties of the generalized Vandermonde determinants obtained in Spie? et al. (Divisibility properties of generalized Vandermonde and Cauchy determinants, Preprint 627, Institute of Mathematics, Polish Academy of Sciences, Warsaw, 2002). This allows us to simplify our main Theorem 2 and obtain Theorem 3 where the most general form of the linear congruence relation is given. 相似文献
18.
Matthew Boylan 《Journal of Number Theory》2003,98(2):377-389
Let F(z)=∑n=1∞a(n)qn denote the unique weight 16 normalized cuspidal eigenform on . In the early 1970s, Serre and Swinnerton-Dyer conjectured that
19.
20.
Yong-Gao Chen 《Journal of Number Theory》2003,98(2):310-319
In this paper we prove that if (r,12)?3, then the set of positive odd integers k such that kr−2n has at least two distinct prime factors for all positive integers n contains an infinite arithmetic progression. The same result corresponding to kr2n+1 is also true. 相似文献