全文获取类型
收费全文 | 2308篇 |
免费 | 44篇 |
国内免费 | 85篇 |
专业分类
化学 | 391篇 |
晶体学 | 7篇 |
力学 | 12篇 |
综合类 | 14篇 |
数学 | 1723篇 |
物理学 | 290篇 |
出版年
2024年 | 5篇 |
2023年 | 10篇 |
2022年 | 14篇 |
2021年 | 20篇 |
2020年 | 16篇 |
2019年 | 79篇 |
2018年 | 72篇 |
2017年 | 31篇 |
2016年 | 21篇 |
2015年 | 24篇 |
2014年 | 85篇 |
2013年 | 234篇 |
2012年 | 35篇 |
2011年 | 157篇 |
2010年 | 142篇 |
2009年 | 142篇 |
2008年 | 165篇 |
2007年 | 196篇 |
2006年 | 152篇 |
2005年 | 111篇 |
2004年 | 79篇 |
2003年 | 69篇 |
2002年 | 66篇 |
2001年 | 33篇 |
2000年 | 40篇 |
1999年 | 31篇 |
1998年 | 31篇 |
1997年 | 17篇 |
1996年 | 58篇 |
1995年 | 38篇 |
1994年 | 44篇 |
1993年 | 30篇 |
1992年 | 32篇 |
1991年 | 34篇 |
1990年 | 17篇 |
1989年 | 12篇 |
1988年 | 7篇 |
1987年 | 17篇 |
1986年 | 6篇 |
1985年 | 13篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1973年 | 4篇 |
排序方式: 共有2437条查询结果,搜索用时 125 毫秒
131.
Denote by
the class of all triangle-free
graphs on n vertices and
m edges. Our main result is
the following sharp threshold, which answers the question for
which densities a typical triangle-free graph is bipartite. Fix
> 0 and let
. If
n/2 m (1 – ) t
3, then almost
all graphs in
are not bipartite, whereas if
m (1 + )t
3, then almost
all of them are bipartite. For m (1 + )t
3, this allows
us to determine asymptotically the number of graphs in
. We also obtain corresponding
results for C
-free graphs, for any
cycle C
of fixed odd length.
Forschergruppe Algorithmen, Struktur, Zufall
supported by Deutsche Forschungsgemeinschaft grant FOR
413/1-1 相似文献
132.
133.
M. Chahboun A. El Kinani M. Oudadess 《Rendiconti del Circolo Matematico di Palermo》2001,50(2):271-284
We examine the structure and the spectral properties of locally uniformlyA-pseudo-convex algebras.
相似文献
134.
Ferenc Móricz 《Journal of Fourier Analysis and Applications》2001,7(6):601-614
A theorem of Fejér states that if a periodic function F is of bounded variation on the closed interval [0, 2π], then the nth
partial sum of its formally differentiated Fourier series divided by n converges to π-1[F(x+0)-F(x-0)] at each point x. The generalization of this theorem for Fourier-Stieltjes series of (nonperiodic) functions of bounded variation
is also well known.
The aim of the present article is to extend these results to the (m, n)th rectangular partial sum of double Fourier or Fourier-Stieltjes
series of a function F(x, y) of bounded variation over the closed square [0, 2π]×[0, 2π] in the sense of Hardy and Krause.
As corollaries, we also obtain the following results:
相似文献
(i) | The terms of the Fourier or Fourier-Stieltjes series of F(x, y) determine the atoms of the (periodic) Borel measure induced by (an appropriate extension of) F. |
(ii) | In the case of periodic functions F(x, y) of bounded variation, the class of double Fourier-Stieltjes series coincides with the class of series that can be obtained from their Fourier series by a formal termwise differentiation with respect to both x and y. |
135.
Chanho Kwon Yong-Hoon Choi Namjoon Kim Jong Shin Yoo Chul-Hak Yang Hyun-Won Kim Seunho Jung 《Journal of inclusion phenomena and macrocyclic chemistry》2000,36(1):55-64
Neutral cyclosophoraoses (unbranched cyclic -1,2-d-glucans) produced by the Rhizo-bium meliloti 2011 were prepared by size exclusion and anion-exchange chromatographic techniques. The degree of polymerization (DP) of isolated cyclosophoraoses was determined by matrix associated laser desorption/ionization mass spectrometry (MALDI/MS) techniques. A family of purified neutral cyclosophoraoses (DP 17–27) was used as a host for the inclusion complexation with hardly soluble ergosterol. High performance liquid chromatographic (HPLC) analysis showed that it induced much enhanced solubility of ergosterol compared to -cyclodextrin. In order to understand the molecular basis of the complex forming ability of cyclosophoraoses, a Monte Carlo (MC) docking-minimization method was used for host-guest complex formation of cyclosophoraoses or -cyclodextrin with ergosterol. From the MC simulation we propose the `hand-shake' mechanism for complexation of cyclosophoraoses with ergosterol. 相似文献
136.
With “hat” denoting the Banach envelope (of a quasi-Banach space) we prove that
if 0<p<1, 0<q<1, ℝ, while
if 0<p<1, 1≤q<+∞, ∝, and
if 1≤p<+∞, 0<q<1, ℝ.
Applications to questions regarding the global interior regularity of solutions to Poisson type problems for the three-dimensional
Lamé system in Lipschitz domains are presented. 相似文献
137.
Georges Pinczon 《Letters in Mathematical Physics》2007,82(2-3):237-253
We give a new proof and an improvement of two Theorems of J. Alev, M.A. Farinati, T. Lambre and A.L. Solotar [1] : the first
one about Hochschild cohomology spaces of some twisted bimodules of the Weyl Algebra W, and the second one about Hochschild cohomology spaces of the smash product G * W (G a finite subgroup of SP (2n)) and, as a consequence, we then give a new proof of a Theorem of P. Etingof and V. Ginzburg (Invent Math 147:243–348, 2002),
which shows that the Symplectic Reflection Algebras are deformations of G * W (and, in fact, all possible ones).
Dedicated to my friend J.-C. Cortet. 相似文献
138.
139.
Gena Puninski 《Journal of Pure and Applied Algebra》2008,212(4):704-717
We construct an element in a direct product of finite dimensional modules over a string algebra such that the pure-injective envelope of this element is a superdecomposable module. 相似文献
140.
Although much discussed, the original intent of Problem 10 of the Moscow Mathematical Papyrus continues to be an unresolved question. This essay proposes a possible solution to the issue by joining together aspects of two theories on the subject advanced in the 1930s by W. W. Struve and T. E. Peet. From this point of beginning it is shown that the problem’s “basket” may originally have been intended to be understood as being of a specific actual size, thus revealing a set of correlations and insights regarding early Middle Kingdom mathematical capabilities and grain measurement concerns. 相似文献