全文获取类型
收费全文 | 10415篇 |
免费 | 764篇 |
国内免费 | 1379篇 |
专业分类
化学 | 3694篇 |
晶体学 | 52篇 |
力学 | 202篇 |
综合类 | 164篇 |
数学 | 6739篇 |
物理学 | 1707篇 |
出版年
2024年 | 7篇 |
2023年 | 104篇 |
2022年 | 148篇 |
2021年 | 253篇 |
2020年 | 251篇 |
2019年 | 303篇 |
2018年 | 293篇 |
2017年 | 314篇 |
2016年 | 237篇 |
2015年 | 227篇 |
2014年 | 380篇 |
2013年 | 1103篇 |
2012年 | 368篇 |
2011年 | 499篇 |
2010年 | 429篇 |
2009年 | 575篇 |
2008年 | 649篇 |
2007年 | 812篇 |
2006年 | 630篇 |
2005年 | 574篇 |
2004年 | 495篇 |
2003年 | 528篇 |
2002年 | 489篇 |
2001年 | 398篇 |
2000年 | 385篇 |
1999年 | 370篇 |
1998年 | 337篇 |
1997年 | 292篇 |
1996年 | 209篇 |
1995年 | 117篇 |
1994年 | 141篇 |
1993年 | 88篇 |
1992年 | 85篇 |
1991年 | 62篇 |
1990年 | 46篇 |
1989年 | 47篇 |
1988年 | 49篇 |
1987年 | 46篇 |
1986年 | 26篇 |
1985年 | 44篇 |
1984年 | 28篇 |
1983年 | 17篇 |
1982年 | 19篇 |
1981年 | 20篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 5篇 |
1973年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
51.
Summary It is shown that the outer automorphism group of a Coxeter groupW of finite rank is finite if the Coxeter graph contains no infinite bonds. A key step in the proof is to show that if the
group is irreducible andΠ
1 andΠ
2 any two bases of the root system ofW, thenΠ
2 = ±ωΠ
1 for some ω εW. The proof of this latter fact employs some properties of the dominance order on the root system introduced by Brink and
Howlett.
This article was processed by the author using the Springer-Verlag TEX PJour1g macro package 1991. 相似文献
52.
53.
本文用变换群理论对运动水平平板混合对流边界层流动的动量、能量和浓度扩散方程进行了分析,得到了与X4/(7-5n)成正比的壁面温度分布和浓度分布,同时壁面运动速度正比于X(3-n)/(7-5n)时存在相似性解.导出了相似性解方程,用四阶Runge-Kutta方法进行了计算,给出了Pr=0.72 和Sc,K1,K2,K3参数下的速度、温度和浓度分布,得出了各参数对流场、温度场的影响。 相似文献
54.
The equivalent geometrical configurations of linear ordered orthogonal arrays are determined when their strengths are 3 and 4. Existence of such geometrical configurations is investigated. They are also useful in the study of (T, M, S)-nets. 相似文献
55.
W. Kockelmann M. Hofmann O. Moze S.J. Kennedy K.H.J. Buschow 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(1):25-32
The element distributions and the magnetic ordering behaviour of compounds RNi10Si2 (R
=
Tb, Dy, Ho, Er, Tm) have been studied by neutron powder diffraction down to temperatures of 1.6 K. The compounds crystallize
in an ordered variant of the ThMn12 structure type in the tetragonal space group P4/nmm. An ordered 1:1 distribution of Ni and Si on sites 4d and 4e, respectively,
corresponds to a modulation vector [0, 0, 1] with respect to the space group I4/mmm of the ThMn12 structure. TbNi10Si2 orders antiferromagnetically below T
N
= 4.5 K with a magnetic propagation vector of [0, 0, 1/2]. The magnetic Tb moments, 8.97(2) /Tb atom at 1.6 K, are aligned along the c-axis. The Ni sites in TbNi10Si2 do not carry any ordered magnetic moments. The compounds with R
=
Dy, Ho, Er, and Tm are paramagnetic down to 1.6 K and 3.0 K, respectively.
Received 10 July 2002 / Received in final form 12 September 2002 Published online 29 October 2002 相似文献
56.
S. Moss de Oliveira P. M. C. de Oliveira F. C. de Sá Barreto 《Journal of statistical physics》1995,78(5-6):1619-1627
Using the finite-size scaling renormalization group, we obtain the two-dimensional flow diagram of the Blume-Capel model forS=1 andS=3/2. In the first case our results are similar to those of mean-field theory, which predicts the existence of first- and second-order transitions with a tricritical point. In the second case, however, our results are different. While we obtain in theS=1 case a phase diagram presenting a multicritical point, the mean-field approach predicts only a second-order transition and a critical endpoint. 相似文献
57.
H. R. Ebrahimi-Vishki M. A. Pourabdollah 《Proceedings of the American Mathematical Society》1997,125(7):2171-2174
The purpose of this paper is to introduce an algebra of functions on a semitopological semigroup and to study these functions from the point of view of universal semigroup compactification. We show that the corresponding semigroup compactification of this algebra is universal with respect to the property of being a nilpotent group.
58.
WANG Li-min CHU De-qing ZHANG Jing-ping WANG Rong-shun 《高等学校化学研究》2006,22(5):631-634
IntroductionDesigns and syntheses of organic molecules withvery high-spin ground states have been a topic of greatinterest[1—8].One of the rational approaches to desig-ning high-spin molecules,which has been proposedand studied by several groups[9,10],in… 相似文献
59.
关于体上分块矩阵的群逆 总被引:1,自引:0,他引:1
本文利用分块矩阵方法.研究了体上两个矩阵乘积的群逆的存在性及表示形式,给出了体上两个矩阵乘积群逆存在的充分必要条件和表示形式.并且在一定条件下.给出了体上分块矩阵的群逆存在性及表示形式. 相似文献
60.
Finitely generated linear semigroups over a field K that have intermediate growth are considered. New classes of such semigroups are found and a conjecture on the equivalence of the subexponential growth of a finitely generated linear semigroup S and the nonexistence of free noncommutative subsemigroups in S, or equivalently the existence of a nontrivial identity satisfied in S, is stated. This ‘growth alternative’ conjecture is proved for linear semigroups of degree 2, 3 or 4. Certain results supporting the general conjecture are obtained. As the main tool, a new combinatorial property of groups is introduced and studied. 相似文献