全文获取类型
收费全文 | 13054篇 |
免费 | 1499篇 |
国内免费 | 1023篇 |
专业分类
化学 | 1432篇 |
晶体学 | 11篇 |
力学 | 1396篇 |
综合类 | 259篇 |
数学 | 7743篇 |
物理学 | 4735篇 |
出版年
2024年 | 23篇 |
2023年 | 103篇 |
2022年 | 181篇 |
2021年 | 172篇 |
2020年 | 301篇 |
2019年 | 327篇 |
2018年 | 351篇 |
2017年 | 427篇 |
2016年 | 477篇 |
2015年 | 339篇 |
2014年 | 659篇 |
2013年 | 950篇 |
2012年 | 622篇 |
2011年 | 794篇 |
2010年 | 669篇 |
2009年 | 864篇 |
2008年 | 973篇 |
2007年 | 916篇 |
2006年 | 856篇 |
2005年 | 709篇 |
2004年 | 663篇 |
2003年 | 549篇 |
2002年 | 525篇 |
2001年 | 389篇 |
2000年 | 426篇 |
1999年 | 327篇 |
1998年 | 304篇 |
1997年 | 305篇 |
1996年 | 215篇 |
1995年 | 199篇 |
1994年 | 146篇 |
1993年 | 122篇 |
1992年 | 97篇 |
1991年 | 71篇 |
1990年 | 80篇 |
1989年 | 62篇 |
1988年 | 67篇 |
1987年 | 43篇 |
1986年 | 36篇 |
1985年 | 34篇 |
1984年 | 31篇 |
1983年 | 16篇 |
1982年 | 25篇 |
1981年 | 24篇 |
1980年 | 14篇 |
1979年 | 10篇 |
1978年 | 17篇 |
1977年 | 19篇 |
1974年 | 8篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
The object of the present investigation is to introduce a new trigonometric method of summation which is both regular and
Fourier effective and determine its status with reference to other methods of summation (see §2-§4) and also give an application
of this method to determine the degree of approximation in a new Banach space of functions conceived as a generalized Holder
metric (see §5). 相似文献
62.
Summary In this note we use Theorem 2.4 in<span lang=EN-US style='font-size:10.0pt;mso-ansi-language:EN-US'>[1]to give a very short
proof of a recent result due to M. Bognár (Theorem A in [3]). We also prove that Bognár's result is in fact equivalent to
the classical Hahn-Mazurkiewicz Theorem. Finally we give generalizations in the non-compact setting. 相似文献
63.
利用Ditzian-Totik光滑模,研究了推广的Kantorovich算子在Ba空间中的逼近,得到逼近的正定理与等价定理.所得结果改进、推广和统一了一些作者的结果. 相似文献
64.
Arup Baksi Bidyut Kumar Roy Rasajit Kumar Bera 《Mathematical and Computer Modelling》2006,44(11-12):1069-1079
The fundamental equations of the problems of generalized thermoelasticity with one relaxation parameter including heat sources in infinite rotating magneto-thermo-viscoelastic media have been derived in the form of a vector matrix differential equation in the Laplace transform domain for a one dimensional problem. These equations have been solved by the eigenvalue approach to determine deformations, stress, and temperature. The results have been compared to those available in the existing literature. The graphs have been drawn to show the effect of rotation in the medium. 相似文献
65.
Jian‐guo Tang 《Mathematical Methods in the Applied Sciences》2006,29(11):1327-1338
An implicit iterative method is applied to solving linear ill‐posed problems with perturbed operators. It is proved that the optimal convergence rate can be obtained after choosing suitable number of iterations. A generalized Morozov's discrepancy principle is proposed for the problems, and then the optimal convergence rate can also be obtained by an a posteriori strategy. The convergence results show that the algorithm is a robust regularization method. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
66.
Zuo-liang Xu 《应用数学学报(英文版)》2007,23(4):629-636
In this paper,we study mixed elastico-plasticity problems in which part of the boundary is known,while the other part of the boundary is unknown and is a free boundary.Under certain conditions,this problemcan be transformed into a Riemann-Hilbert boundary value problem for analytic functions and a mixed boundaryvalue problem for complex equations.Using the theory of generalized analytic functions,the solvability of theproblem is discussed. 相似文献
67.
68.
G.J. Zalmai Qing-hong Zhang 《应用数学学报(英文版)》2007,23(2):217-234
In this paper,we discuss a large number of sets of global parametric sufficient optimality condi-tions under various gcneralized (η,ρ)-invexity assumptions for a semi-infinite minmax fractional programmingproblem. 相似文献
69.
J. J. EGOZCUE J. L. DIAZ-BARRERO V. PAWLOWSKY-GLAHN 《数学学报(英文版)》2006,22(4):1175-1182
The set of probability functions is a convex subset of L1 and it does not have a linear space structure when using ordinary sum and multiplication by real constants. Moreover, difficulties arise when dealing with distances between densities. The crucial point is that usual distances are not invariant under relevant transformations of densities. To overcome these limitations, Aitchison's ideas on compositional data analysis are used, generalizing perturbation and power transformation, as well as the Aitchison inner product, to operations on probability density functions with support on a finite interval. With these operations at hand, it is shown that the set of bounded probability density functions on finite intervals is a pre-Hilbert space. A Hilbert space of densities, whose logarithm is square-integrable, is obtained as the natural completion of the pre-Hilbert space. 相似文献
70.
利用关于乘积分布密度的相对熵和相对熵率的概念,建立了相依连续型随机变量序列关于参考微分熵的一类强偏差定理,证明中给出了将Laplace变换应用于微分熵强偏差定理的研究的一种途径. 相似文献