全文获取类型
收费全文 | 32971篇 |
免费 | 1362篇 |
国内免费 | 1562篇 |
专业分类
化学 | 12560篇 |
晶体学 | 229篇 |
力学 | 731篇 |
综合类 | 66篇 |
数学 | 17253篇 |
物理学 | 5056篇 |
出版年
2024年 | 62篇 |
2023年 | 514篇 |
2022年 | 372篇 |
2021年 | 402篇 |
2020年 | 694篇 |
2019年 | 863篇 |
2018年 | 744篇 |
2017年 | 719篇 |
2016年 | 763篇 |
2015年 | 814篇 |
2014年 | 1070篇 |
2013年 | 2887篇 |
2012年 | 1407篇 |
2011年 | 2098篇 |
2010年 | 1580篇 |
2009年 | 2109篇 |
2008年 | 2342篇 |
2007年 | 2155篇 |
2006年 | 1672篇 |
2005年 | 1342篇 |
2004年 | 1156篇 |
2003年 | 1063篇 |
2002年 | 1213篇 |
2001年 | 706篇 |
2000年 | 630篇 |
1999年 | 708篇 |
1998年 | 552篇 |
1997年 | 472篇 |
1996年 | 525篇 |
1995年 | 497篇 |
1994年 | 467篇 |
1993年 | 351篇 |
1992年 | 319篇 |
1991年 | 229篇 |
1990年 | 207篇 |
1989年 | 212篇 |
1988年 | 155篇 |
1987年 | 185篇 |
1986年 | 161篇 |
1985年 | 243篇 |
1984年 | 186篇 |
1983年 | 121篇 |
1982年 | 189篇 |
1981年 | 166篇 |
1980年 | 118篇 |
1979年 | 71篇 |
1978年 | 91篇 |
1977年 | 98篇 |
1976年 | 86篇 |
1974年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Summary We consider the one dimensional nearest neighbors asymmetric simple exclusion process with ratesq andp for left and right jumps respectively;q<p. Ferrari et al. (1991) have shown that if the initial measure isv
,
, a product measure with densities and to the left and right of the origin respectively, <, then there exists a (microscopic) shock for the system. A shock is a random positionX
t
such that the system as seen from this position at timet has asymptotic product distributions with densities and to the left and right of the origin respectively, uniformly int. We compute the diffusion coefficient of the shockD=lim
t
t
–1(E(X
t
)2–(EX
t
)2) and findD=(p–q)(–)–1((1–)+(1–)) as conjectured by Spohn (1991). We show that in the scale
the position ofX
t
is determined by the initial distribution of particles in a region of length proportional tot. We prove that the distribution of the process at the average position of the shock converges to a fair mixture of the product measures with densities and . This is the so called dynamical phase transition. Under shock initial conditions we show how the density fluctuation fields depend on the initial configuration. 相似文献
42.
David Cruz-Uribe 《Integral Equations and Operator Theory》1994,20(2):231-237
In this note I give necessary and sufficient conditions on outer functionsf andg for the operator
to be bounded and invertible on H2. I also discuss the relationship of this question to two open questions in operator theory and weighted norm inequalities. 相似文献
43.
Summary In this paper it is proved that, for any positive integern 2, 3 (mod 4),n 7, there exists an incomplete idempotent Schröder quasigroup with one hole of size two IISQ(n, 2) except forn = 10. It is also proved that for any positive integern 0, 1 (mod 4), there exists an idempotent Schröder quasigroup ISQ(n) except forn = 5 and 9. These results completely determine the spectrum of ISQ(n) and provide an application to the packing of a class of edge-coloured block designs.Research supported by NSERC grant A-5320.Research supported by NSFC grant 19231060-2. 相似文献
44.
45.
V. Suresh 《K-Theory》1996,10(6):597-610
Let X be a smooth projective surface over a number field k. Let (CH0(X)) denote the Chow group of zero-cyles modulo rational equivalence on X. Let CH0(X) be the subgroup of CH
0(X) consisting of classes which vanish when going over to an arbitrary completion of k. Bloch put forward a conjecture asserting that this group is isomorphic to the Tate-Shafarevich group of a certain Galois module atttached to X. In this paper, we disprove this general conjecture. We produce a conic bundle X over an elliptic curve, for which the group (CH0(X) is not zero, but the Galois-theoretic Tate-Shafarevich group vanishes. 相似文献
46.
Yong Zhang 《Order》1996,13(4):365-367
G. Grätzer, H. Lakser, and E. T. Schmidt proved that every distributive lattice with n join-irreducible elements can be represented as the congruence lattice of a small lattice L, that is, a lattice L with O(n
2
) elements. G. Grätzer, I. Rival, and N. Zaguia proved that, for any <2, O(n
2
) can not be improved to O(n
). In this note we show that the theorem about small representation can be improved further to get a more delicate result. 相似文献
47.
Ser Peow Tan 《Geometriae Dedicata》1996,62(2):209-225
Let M be a compact orientable surface with nonempty boundary (x(M)<0) and fundamental group . Let be a geodesic on M (with a fixed hyperbolic structure), and let W be a (cyclically reduced) word in a fixed set
of generators of which represents . In this paper, we give an algorithm to count the number of self-intersections of in terms of W, generalizing a result of Birman and Series, where an algorithm was given to decide if was simple. Some applications of the algorithm to surfaces with one boundary and the Markoff spectrum are also given. 相似文献
48.
One more model of aq-harmonic oscillator based on theq-orthogonal polynomials of Al-Salam and Carlitz is discussed. The explicit form ofq-creation andq-annihilation operators,q-coherent states and an analog of the Fourier transformation are established. A connection of the kernel of this transform with a family of self-dual biorthogonal rational functions is observed. 相似文献
49.
J. Czarnowska 《Periodica Mathematica Hungarica》1993,26(2):101-110
To 80th birthday of Paul Erds 相似文献
50.
Israel Gohberg Naum Krupnik Ilya Spitkovsky 《Integral Equations and Operator Theory》1993,17(3):322-337
The Banach algebra generated by one-dimensional linear singular integral operators with matrix valued piecewise continuous coefficients in the spaceL
p
(,) with an arbitrary weight is studied. The contour consists of a finite number of closed curves and open arcs with satisfy the Carleson condition. The contour may have a finite number of points of selfintersection. The symbol calculus in this algebra is the main result of the paper. 相似文献