全文获取类型
收费全文 | 20844篇 |
免费 | 476篇 |
国内免费 | 164篇 |
专业分类
化学 | 1344篇 |
晶体学 | 64篇 |
力学 | 155篇 |
综合类 | 18篇 |
数学 | 18730篇 |
物理学 | 1173篇 |
出版年
2023年 | 42篇 |
2022年 | 72篇 |
2021年 | 64篇 |
2020年 | 96篇 |
2019年 | 415篇 |
2018年 | 445篇 |
2017年 | 240篇 |
2016年 | 216篇 |
2015年 | 256篇 |
2014年 | 503篇 |
2013年 | 1186篇 |
2012年 | 582篇 |
2011年 | 1242篇 |
2010年 | 1040篇 |
2009年 | 1286篇 |
2008年 | 1524篇 |
2007年 | 1573篇 |
2006年 | 1109篇 |
2005年 | 810篇 |
2004年 | 671篇 |
2003年 | 563篇 |
2002年 | 454篇 |
2001年 | 401篇 |
2000年 | 390篇 |
1999年 | 523篇 |
1998年 | 493篇 |
1997年 | 425篇 |
1996年 | 487篇 |
1995年 | 512篇 |
1994年 | 458篇 |
1993年 | 418篇 |
1992年 | 400篇 |
1991年 | 248篇 |
1990年 | 222篇 |
1989年 | 255篇 |
1988年 | 151篇 |
1987年 | 152篇 |
1986年 | 150篇 |
1985年 | 221篇 |
1984年 | 201篇 |
1983年 | 116篇 |
1982年 | 188篇 |
1981年 | 164篇 |
1980年 | 109篇 |
1979年 | 82篇 |
1978年 | 116篇 |
1977年 | 75篇 |
1976年 | 62篇 |
1975年 | 26篇 |
1974年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
George E. Andrews 《Annals of Combinatorics》1999,3(2-4):115-130
We study the number of solutions of the Diophantine equationn=x
1
x
2+x
2
x
3+x
3
x
4+...+x
k
x
k+1 The combinatorial interpretation of this equation provides the name stacked lattices boxes. The study of these objects unites three separate threads in number theory: (1) the Liouville methods, (2) MacMahon's partitions withk different parts, (3) the asymptotics of divisor sums begun by Ingham.Partially supported by National Science Foundation Grant DMS-9206993, USA. 相似文献
942.
Tamás Szamuely 《K-Theory》1999,18(2):173-179
For a proper smooth variety X defined over a local field k, unramified class field theory investigates the reciprocity map X: SK1(X) ab
1(X) as introduced by S. Saito. We study this map in the case when X is a surface admitting a proper surjection onto a smooth geometrically connected curve C with a smooth conic as generic fibre. Without any assumption on the reduction of C, we prove that X is injective modulo n for all n invertible in k and its cokernel is the same as that of C. 相似文献
943.
Roy Joshua 《K-Theory》1999,17(1):1-35
Let G denote a complex linear algebraic group. In this paper we establish several forms of equivariant Riemann–Roch valid for the category of Gquasiprojective complex varieties. The main application is to the operation of convolution that appears in the construction of modules over convolution algebras, for example the Hecke algebras associated to a complex reductive group as well as in the representation theory of quantum groups. The paper concludes with a discussion of some of these applications. The results in this paper hold mostly at the level of Grothendieck groups. The second part of this paper will discuss the extension to higher Ktheory in detail. 相似文献
944.
姚奎 《浙江大学学报(理学版)》1999,(1)
本文考虑用TchebychefFourier级数的ValéePousin平均逼近函数类Lipα,在f(x)∈C[-1,1]时获得了逼近阶及逼近误差的表达式,推广并较大地改进了文献[1,2]中的有关结果. 相似文献
945.
946.
We show that for any simple piecewise Ljapunov contour there exists a power weight such that the essential norm |S
| in the spaceL
2(, ) does not depend on the angles of the contour and it is given by formula (2). All such weights are described. For the union =12 of two simple piecewise Lyapunov curves we prove that the essential norm |S
| inL
2() is minimal if both 1 and 2 are smooth in some neighborhoods of the common points. It is the case when the norm |S
| in the spaceL
2() as well as inL
2(, ) does not depend on the values of the angles and it can be calculated by formula (5). 相似文献
947.
Daoxing Xia 《Integral Equations and Operator Theory》1999,33(4):489-506
This paper studies the class of pure operatorsA on a Hilbert space
satisfying dimK
A
<, where
. The main tool is a pair of matrices
and
. A reproducing kernel Hilbert space model is introduced for a subclass of this class of operators. Some theorems are established for some subnormal operators as well as hyponormal operators in this class. 相似文献
948.
We present several results concerning the asymptotic behavior of (random) infinite products of generic sequences of positive linear operators on an ordered Banach space. In addition to a weak ergodic theorem we also obtain convergence to an operator of the formf(·) wheref is a continuous linear functional and is a common fixed point. 相似文献
949.
Christian Mazza 《Probability Theory and Related Fields》1999,113(2):171-190
We consider the ±J spin glass on a finite graph G=(V,E), with i.i.d. couplings. Our approach considers the Z
2 local gauge invariance of the system. We see the gauge group as a graph theoretic linear code ? over GF(2). The gauge is fixed by choosing a convenient linear supplement of ?. Assuming some relation between the disorder parameter
p and the inverse temperature of the thermal bath β
pb
, we study percolation in the random interaction random cluster model, and extend the results to dilute spin glasses.
Received: 5 May 1997 / Revised version: 9 April 1998 相似文献
950.
On the stability of wavelet and Gabor frames (Riesz bases) 总被引:6,自引:0,他引:6
Zhang Jing 《Journal of Fourier Analysis and Applications》1999,5(1):105-125
If the sequence of functions j, k is a wavelet frame (Riesz basis) or Gabor frame (Riesz basis), we obtain its perturbation system j,k which is still a frame (Riesz basis) under very mild conditions. For example, we do not need to know that the support of or
is compact as in [14]. We also discuss the stability of irregular sampling problems. In order to arrive at some of our results, we set up a general multivariate version of Littlewood-Paley type inequality which was originally considered by Lemarié and Meyer [17], then by Chui and Shi [9], and Long [16]. 相似文献