全文获取类型
收费全文 | 268827篇 |
免费 | 3119篇 |
国内免费 | 819篇 |
专业分类
化学 | 139983篇 |
晶体学 | 4296篇 |
力学 | 11414篇 |
综合类 | 1篇 |
数学 | 31441篇 |
物理学 | 85630篇 |
出版年
2021年 | 2000篇 |
2020年 | 2365篇 |
2019年 | 2610篇 |
2018年 | 3528篇 |
2017年 | 3409篇 |
2016年 | 5338篇 |
2015年 | 3534篇 |
2014年 | 5117篇 |
2013年 | 12535篇 |
2012年 | 9879篇 |
2011年 | 11908篇 |
2010年 | 8194篇 |
2009年 | 7880篇 |
2008年 | 10773篇 |
2007年 | 10674篇 |
2006年 | 9935篇 |
2005年 | 9017篇 |
2004年 | 8138篇 |
2003年 | 7079篇 |
2002年 | 6962篇 |
2001年 | 7724篇 |
2000年 | 5939篇 |
1999年 | 4676篇 |
1998年 | 3911篇 |
1997年 | 3756篇 |
1996年 | 3692篇 |
1995年 | 3310篇 |
1994年 | 3265篇 |
1993年 | 3365篇 |
1992年 | 3449篇 |
1991年 | 3548篇 |
1990年 | 3296篇 |
1989年 | 3186篇 |
1988年 | 3240篇 |
1987年 | 3126篇 |
1986年 | 2966篇 |
1985年 | 4054篇 |
1984年 | 4234篇 |
1983年 | 3393篇 |
1982年 | 3592篇 |
1981年 | 3503篇 |
1980年 | 3393篇 |
1979年 | 3507篇 |
1978年 | 3597篇 |
1977年 | 3522篇 |
1976年 | 3612篇 |
1975年 | 3282篇 |
1974年 | 3290篇 |
1973年 | 3358篇 |
1972年 | 2326篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
51.
We calculate the leading and next-to-leading logarithmic resummed distribution for the jet broadening in deep inelastic scattering,
as well as the power correction for both the distribution and mean value. A truncation of the answer at NLL accuracy, as is
standard, leads to unphysical divergences. We discuss their origin and show how the problem can be resolved. We then examine
DIS specific procedures for matching to fixed order calculations and compare our results to the data. One of the tools developed
for the comparison is an NLO parton distribution evolution code. When compared to PDF sets from MRST and CTEQ it reveals limited
discrepancies in both.
Received: 16 October 2001 / Published online: 12 April 2002 相似文献
52.
53.
It is proved that biorthogonal polynomials obey two different kinds of Christoffel-Darboux-type formulae, one linking polynomials with a different parameter and one combining polynomials with different degrees. This is used to produce a mixed recurrence relation, which is valid for all biorthogonal polynomials. This recurrence relation establishes several results on interlacing property of zeros of successive biorthogonal polynomials and leads to a new result on the interlace of zeros of orthogonal polynomials (of equal degrees) with respect to two distributionsdψ(x) andx p dψ(x), 0<p≤1, with support in either [0, 1] or [1, ∞). 相似文献
54.
55.
Lubomír Kubáček 《Applications of Mathematics》2006,51(6):565-582
Some remarks to problems of point and interval estimation, testing and problems of outliers are presented in the case of multivariate
regression model.
This work was supported by the Council of Czech Government J14/98:153100011. 相似文献
56.
We establish sufficient conditions for the existence and uniqueness of a periodic solution of a system of linear differential equations with a small parameter and a degenerate matrix of coefficients of derivatives in the case of a multiple spectrum of a boundary matrix pencil. We construct asymptotics of this solution. 相似文献
57.
58.
The structural evolution in amorphous silicon and germanium thin films has been investigated by high-resolution transmission electron microscopy (HRTEM) in conjunction with autocorrelation function (ACF) analysis. The results established that the structure of as-deposited semiconductor films is of a high density of nanocrystallites embedded in the amorphous matrix. In addition, from ACF analysis, the structure of a-Ge is more ordered than that of a-Si. The density of embedded nanocrystallites in amorphous films was found to diminish with annealing temperature first, then to increase. The conclusions also corroborate well with the results of diminished medium-range order in annealed amorphous films determined previously by a variable coherence microscopy method. 相似文献
59.
Ricardo Celorrio Vı́ctor Domínguez Francisco-Javier Sayas 《Comptes Rendus Mathematique》2002,334(10):923-926
In this work we study the solution of Laplace's equation in a domain with holes by an iteration consisting of splitting the problem in an exterior one, around the holes, plus an interior problem in the unholed domain. We show the existence of a decomposition of the solution when the exterior problem is represented by means of a single-layer protential. Also, for the three-dimensional case and with some adjustments for the two-dimensional case, we prove convergence of the method by writing the iteration as a Jacobi iteration for an operator equation and studying the spectrum of the iteration operator. To cite this article: R. Celorrio et al., C. R. Acad. Sci. Paris, Ser. I 334 (2002) 923–926. 相似文献
60.