全文获取类型
收费全文 | 30020篇 |
免费 | 1702篇 |
国内免费 | 2486篇 |
专业分类
化学 | 6555篇 |
晶体学 | 351篇 |
力学 | 1433篇 |
综合类 | 368篇 |
数学 | 19994篇 |
物理学 | 5507篇 |
出版年
2023年 | 267篇 |
2022年 | 344篇 |
2021年 | 439篇 |
2020年 | 528篇 |
2019年 | 607篇 |
2018年 | 583篇 |
2017年 | 690篇 |
2016年 | 708篇 |
2015年 | 583篇 |
2014年 | 1002篇 |
2013年 | 1985篇 |
2012年 | 1169篇 |
2011年 | 1422篇 |
2010年 | 1315篇 |
2009年 | 2155篇 |
2008年 | 2246篇 |
2007年 | 2124篇 |
2006年 | 1936篇 |
2005年 | 1516篇 |
2004年 | 1261篇 |
2003年 | 1348篇 |
2002年 | 1406篇 |
2001年 | 1030篇 |
2000年 | 982篇 |
1999年 | 925篇 |
1998年 | 857篇 |
1997年 | 745篇 |
1996年 | 507篇 |
1995年 | 413篇 |
1994年 | 384篇 |
1993年 | 277篇 |
1992年 | 247篇 |
1991年 | 211篇 |
1990年 | 167篇 |
1989年 | 131篇 |
1988年 | 138篇 |
1987年 | 109篇 |
1986年 | 100篇 |
1985年 | 158篇 |
1984年 | 155篇 |
1983年 | 82篇 |
1982年 | 135篇 |
1981年 | 132篇 |
1980年 | 117篇 |
1979年 | 85篇 |
1978年 | 87篇 |
1977年 | 94篇 |
1976年 | 67篇 |
1974年 | 59篇 |
1973年 | 47篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
In this paper, the authors studied certain properties of the estimate of Liang and Krishnaiah (1985, J. Multivariate Anal. 16, 162–172) for multivariate binary density. An alternative shrinkage estimate is also obtained. The above results are generalized to general orthonormal systems. 相似文献
22.
23.
Yoel Shkolnisky Mark Tygert Vladimir Rokhlin 《Applied and Computational Harmonic Analysis》2006,21(3):413-420
Many signals encountered in science and engineering are approximated well by bandlimited functions. We provide suitable error bounds for the approximation of bandlimited functions by linear combinations of certain special functions—the prolate spheroidal wave functions of order 0. The coefficients in the approximating linear combinations are given explicitly via appropriate quadrature formulae. 相似文献
24.
P. Nithiananthi 《Solid State Communications》2006,137(8):427-430
The binding energies of a hydrogenic donor both in the parabolic and non-parabolic conduction band model within the effective mass approximation have been computed for the low-dimensional semiconducting systems (LDSS) like quantum well, quantum well wire and quantum dot taking GaAs/AlxGa1−xAs systems as an example. It is observed that the effect of non-parabolicity is not effective when the system goes to lower dimensionality. The diamagnetic susceptibility of a hydrogenic donor impurity has also been computed in these LDSS in the infinite barrier model. Since no theoretical or experimental works on the diamagnetic susceptibility of LDSS are available in the literature, as a realistic case the diamagnetic susceptibility has been computed in the finite barrier model (x=0.3) for a quantum well and the results are discussed in the light of semiconductor-metal transition. 相似文献
25.
Well-Posedness by Perturbations of Variational Problems 总被引:3,自引:0,他引:3
Lemaire B. Ould Ahmed Salem C. Revalski J. P. 《Journal of Optimization Theory and Applications》2002,115(2):345-368
In this paper, we consider the extension of the notion of well-posedness by perturbations, introduced by Zolezzi for optimization problems, to other related variational problems like inclusion problems and fixed-point problems. Then, we study the conditions under which there is equivalence of the well-posedness in the above sense between different problems. Relations with the so-called diagonal well-posedness are also given. Finally, an application to staircase iteration methods is presented. 相似文献
26.
G. Dattoli 《Journal of Mathematical Analysis and Applications》2002,269(2):716-725
Bilateral generating functions are those involving products of different types of polynomials. We show that operational methods offer a powerful tool to derive these families of generating functions. We study cases relevant to products of Hermite polynomials with Laguerre, Legendre and other polynomials. We also propose further extensions of the method which we develop here. 相似文献
27.
Zhong-Qing Wang 《Journal of Mathematical Analysis and Applications》2002,274(1):374-403
An orthogonal system of rational functions is discussed. Some inverse inequalities, imbedding inequalities and approximation results are obtained. Two model problems are considered. The stabilities and convergences of proposed rational spectral schemes and rational pseudospectral schemes are proved. The techniques used in this paper are also applicable to other problems on the whole line. Numerical results show the efficiency of this approach. 相似文献
28.
Filippo Bracci Roberto Tauraso Fabio Vlacci 《Journal of Mathematical Analysis and Applications》2002,270(2):1131-473
Let f,g be two commuting holomorphic self-maps of the unit disc. If f and g agree at the common Wolff point up to a certain order of derivatives (no more than 3 if the Wolff point is on the unit circle), then f≡g. 相似文献
29.
30.