全文获取类型
收费全文 | 5868篇 |
免费 | 201篇 |
国内免费 | 12篇 |
专业分类
化学 | 3564篇 |
晶体学 | 39篇 |
力学 | 212篇 |
数学 | 948篇 |
物理学 | 1318篇 |
出版年
2023年 | 39篇 |
2022年 | 28篇 |
2021年 | 48篇 |
2020年 | 90篇 |
2019年 | 61篇 |
2018年 | 72篇 |
2017年 | 59篇 |
2016年 | 137篇 |
2015年 | 150篇 |
2014年 | 132篇 |
2013年 | 254篇 |
2012年 | 341篇 |
2011年 | 372篇 |
2010年 | 211篇 |
2009年 | 176篇 |
2008年 | 279篇 |
2007年 | 289篇 |
2006年 | 273篇 |
2005年 | 282篇 |
2004年 | 267篇 |
2003年 | 196篇 |
2002年 | 185篇 |
2001年 | 91篇 |
2000年 | 81篇 |
1999年 | 71篇 |
1998年 | 58篇 |
1997年 | 73篇 |
1996年 | 50篇 |
1995年 | 64篇 |
1994年 | 46篇 |
1993年 | 47篇 |
1992年 | 51篇 |
1991年 | 41篇 |
1990年 | 44篇 |
1989年 | 39篇 |
1988年 | 57篇 |
1987年 | 44篇 |
1985年 | 36篇 |
1984年 | 40篇 |
1983年 | 32篇 |
1982年 | 40篇 |
1981年 | 56篇 |
1980年 | 40篇 |
1979年 | 32篇 |
1978年 | 45篇 |
1977年 | 35篇 |
1976年 | 38篇 |
1975年 | 31篇 |
1974年 | 31篇 |
1908年 | 30篇 |
排序方式: 共有6081条查询结果,搜索用时 31 毫秒
31.
32.
In multivariate statistical analysis, several authors have studied the total positivity properties of the generalized (0 F 1) hypergeometric function of two real symmetric matrix arguments. In this paper, we make use of zonal polynomial expansions to obtain a new proof of a result that these 0 F 1functions fail to satisfy certain pairwise total positivity properties; this proof extends both to arbitrary generalized ( r F s ) functions of two matrix arguments and to the generalized hypergeometric functions of Hermitian matrix arguments. In the case of the generalized hypergeometric functions of two Hermitian matrix arguments, we prove that these functions satisfy certain modified pairwise TP2properties; the proofs of these results are based on Sylvester's formula for compound determinants and the condensation formula of C. L. Dodgson [Lewis Carroll] (1866). 相似文献
33.
Let R be a local ring and let (x
1, …, x
r) be part of a system of parameters of a finitely generated R-module M, where r < dimR
M. We will show that if (y
1, …, y
r) is part of a reducing system of parameters of M with (y
1, …, y
r) M = (x
1, …, x
r) M then (x
1, …, x
r) is already reducing. Moreover, there is such a part of a reducing system of parameters of M iff for all primes P ε Supp M ∩ V
R(x
1, …, x
r) with dimR
R/P = dimR
M − r the localization M
P of M at P is an r-dimensional Cohen-Macaulay module over R
P.
Furthermore, we will show that M is a Cohen-Macaulay module iff y
d is a non zero divisor on M/(y
1, …, y
d−1) M, where (y
1, …, y
d) is a reducing system of parameters of M (d:= dimR
M). 相似文献
34.
Henrik L. Pedersen 《Mediterranean Journal of Mathematics》2007,4(4):419-433
We show that the remainder in Ruijsenaars’ asymptotic expansion of the logarithm of Barnes double gamma function gives rise
to a completely monotone function. Fourier expansions of the multiple Bernoulli polynomials are also obtained.
Research supported by the Carlsberg Foundation. 相似文献
35.
Henrik Flyvbjerg 《Physica A》2004,340(4):552-558
The nature of self-organized criticality (SOC) is pin-pointed with a simple mechanical model: a pinball machine. Its phase space is fully parameterized by two integer variables, one describing the state of an on-going game, the other describing the state of the machine. This is the simplest possible SOC system, having only two degrees of freedom and no spatial correlations, yet is not solvable by analytical means. 相似文献
36.
C. Donzaud S. Czajkowski P. Armbruster M. Bernas C. Böckstiegel P. Dessagne H. Geissel E. Hanelt A. Heinz C. Kozhuharov C. Miehé G. Münzenberg M. Pfützner W. Schwab C. Stéphan K. Sümmerer L. Tassan-Got B. Voss 《The European Physical Journal A - Hadrons and Nuclei》1998,1(4):407-426
Projectile fission of 750 AMeV 238U-ions interacting with a Pb target was studied by means of the spectrometer FRS, GSI-Darmstadt. One of the two fission fragments
was detected with a transmission of few percent and identified in mass and charge. Low-energy fission (E* < 25 MeV) events were selected by their magnetic rigidity. Whereas the production of asymmetric fission events is dominated
by the GDR excitation, very asymmetric fission and symmetric fission take place after a GQR or DGDR excitation or after a
nuclear interaction. Cross sections of more than 250 isotopes were measured. Isotopic distributions of low-energy fission
were reconstructed for elements from Se to Te. The fission modes SI, SII and SL were clearly shown in these distributions
and in the mass and TKE distributions. Charge polarization and mass dispersion were deduced for each fission mode. Finally,
the characteristics of the low-energy fission process explain the production rates of neutron-rich species.
Received: 14 July 1997 / Revised version: 6 October 1997 相似文献
37.
38.
In this article, local optimality in multiobjective combinatorial optimization is used as a baseline for the design and analysis
of two iterative improvement algorithms. Both algorithms search in a neighborhood that is defined on a collection of sets
of feasible solutions and their acceptance criterion is based on outperformance relations. Proofs of the soundness and completeness
of these algorithms are given. 相似文献
39.
We compute the entropyh
A
(
U
) in the sense of Connes, Narnhofer and Thirring of Bogoliubov automorphisms
U
of the CAR-algebra with respect to invariant quasifree states
A
with 0A1 having pure point spectrum.Supported in part by a grant from the National Science Foundation 相似文献
40.