全文获取类型
收费全文 | 24585篇 |
免费 | 3850篇 |
国内免费 | 2371篇 |
专业分类
化学 | 2795篇 |
晶体学 | 74篇 |
力学 | 2067篇 |
综合类 | 617篇 |
数学 | 14806篇 |
物理学 | 10447篇 |
出版年
2024年 | 38篇 |
2023年 | 199篇 |
2022年 | 475篇 |
2021年 | 544篇 |
2020年 | 574篇 |
2019年 | 586篇 |
2018年 | 607篇 |
2017年 | 796篇 |
2016年 | 881篇 |
2015年 | 727篇 |
2014年 | 1389篇 |
2013年 | 1709篇 |
2012年 | 1379篇 |
2011年 | 1674篇 |
2010年 | 1453篇 |
2009年 | 1640篇 |
2008年 | 1636篇 |
2007年 | 1827篇 |
2006年 | 1609篇 |
2005年 | 1481篇 |
2004年 | 1225篇 |
2003年 | 1139篇 |
2002年 | 956篇 |
2001年 | 872篇 |
2000年 | 816篇 |
1999年 | 677篇 |
1998年 | 582篇 |
1997年 | 566篇 |
1996年 | 420篇 |
1995年 | 337篇 |
1994年 | 271篇 |
1993年 | 214篇 |
1992年 | 186篇 |
1991年 | 152篇 |
1990年 | 158篇 |
1989年 | 112篇 |
1988年 | 111篇 |
1987年 | 85篇 |
1986年 | 76篇 |
1985年 | 98篇 |
1984年 | 73篇 |
1983年 | 47篇 |
1982年 | 73篇 |
1981年 | 69篇 |
1980年 | 44篇 |
1979年 | 37篇 |
1978年 | 34篇 |
1977年 | 29篇 |
1976年 | 32篇 |
1973年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
181.
The existing model for multivariate skew normal data does not cohere with the joint distribution of a random sample from a
univariate skew normal distribution. This incoherence causes awkward interpretation for data analysis in practice, especially
in the development of the sampling distribution theory. In this paper, we propose a refined model that is coherent with the
joint distribution of the univariate skew normal random sample, for multivariate skew normal data. The proposed model extends
and strengthens the multivariate skew model described in Azzalini (1985,Scandinavian Journal of Statistics,12, 171–178). We present a stochastic representation for the newly proposed model, and discuss a bivariate setting, which confirms
that the newly proposed model is more plausible than the one given by Azzalini and Dalla Valle (1996,Biometrika,83, 715–726). 相似文献
182.
全变差有界函数列的一致(R)可积性 总被引:4,自引:0,他引:4
给出了一致有界单调函数列一致可积性定理 ,由此得出全变差序列有界的收敛函数列的一致可积性 .说明了该结论可判断一些非一致收敛函数列的逐项积分性质 . 相似文献
183.
讨论了W12[a,b]能否扩大为含有有间断点函数的再生核空间的问题.结论是:若再生核空间W W12[a,b]含有有间断点的函数,则间断点必固定、间断点个数必有限且非端点a,b.进一步,我们构造了函数含有n个间断点的再生核空间并给出其再生核表达式. 相似文献
184.
185.
186.
A fourth‐order compact finite difference scheme on the nine‐point 2D stencil is formulated for solving the steady‐state Navier–Stokes/Boussinesq equations for two‐dimensional, incompressible fluid flow and heat transfer using the stream function–vorticity formulation. The main feature of the new fourth‐order compact scheme is that it allows point‐successive overrelaxation (SOR) or point‐successive underrelaxation iteration for all Rayleigh numbers Ra of physical interest and all Prandtl numbers Pr attempted. Numerical solutions are obtained for the model problem of natural convection in a square cavity with benchmark solutions and compared with some of the accurate results available in the literature. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
187.
Yi Qin Thomas Trautmann 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,84(1):105-114
As a computationally effective tool, the first-order term of the radiative perturbation theory has been computed successfully, and has been applied in a number of areas. In this article, we develop the computational expressions for the higher-order terms of the perturbation expansion in a plane parallel atmosphere. These expressions are then implemented, and numerical results for some typical cases are presented. These results indicate that the computation is successful and that the higher-order terms are essential in cases where the first-order term alone cannot predict the perturbation with sufficient accuracy. 相似文献
188.
J. J. Rehr 《Foundations of Physics》2003,33(12):1735-1742
The Golden rule expression for x-ray absorption spectra (XAS) is typically calculated within a one-particle (quasiparticle) approximation and generally leads to good agreement between theory and experiment. The fact that a quasiparticle approximation works fairly well is surprising, since it neglects satellite excitations and intrinsic losses due to a suddenly created core-hole. The resolution of this paradox requires physics beyond the independent particle approximation. This is discussed here using an effective Green's function formulation based on a quasi-boson model that takes interference between inelastic losses into account. This approach shows that inelastic excitations such as multi-electron excitations tend to be suppressed, and that the XAS is given by a broadened quasiparticle particle approximation, together with weak satellite structure and edge singularity effects. 相似文献
189.
A set of invariants describing the limit regimes of braking disk-type wound composite flywheels is suggested. The limit regime is determined by using a linear failure criterion. It is shown that, for generating short-time impulses of very high power, a set of small identical flywheels is more effective than one large flywheel with an equivalent mass. Particular examples illustrating the theory considered are discussed. 相似文献
190.
Shy-Der Lin 《Journal of Mathematical Analysis and Applications》2004,294(2):399-411
The main object of this paper is to investigate several general families of hypergeometric polynomials and their associated single-, double-, and triple-integral representations. Some known or new consequences of the general results presented here, involving such classical orthogonal polynomials as the Jacobi, Laguerre, Hermite, and Bessel polynomials, and various other relatively less familiar hypergeometric polynomials, are also considered. Each of the integral representations, which are derived in this paper, may be viewed also as a linearization relationship for the product of two different members of the associated family of hypergeometric polynomials. 相似文献