全文获取类型
收费全文 | 22895篇 |
免费 | 4410篇 |
国内免费 | 2710篇 |
专业分类
化学 | 1501篇 |
晶体学 | 140篇 |
力学 | 3308篇 |
综合类 | 833篇 |
数学 | 15321篇 |
物理学 | 8912篇 |
出版年
2024年 | 157篇 |
2023年 | 496篇 |
2022年 | 552篇 |
2021年 | 579篇 |
2020年 | 448篇 |
2019年 | 432篇 |
2018年 | 294篇 |
2017年 | 470篇 |
2016年 | 559篇 |
2015年 | 680篇 |
2014年 | 1333篇 |
2013年 | 1040篇 |
2012年 | 1284篇 |
2011年 | 1603篇 |
2010年 | 1459篇 |
2009年 | 1449篇 |
2008年 | 1522篇 |
2007年 | 1334篇 |
2006年 | 1222篇 |
2005年 | 1424篇 |
2004年 | 1326篇 |
2003年 | 1288篇 |
2002年 | 1034篇 |
2001年 | 1044篇 |
2000年 | 958篇 |
1999年 | 782篇 |
1998年 | 743篇 |
1997年 | 669篇 |
1996年 | 619篇 |
1995年 | 590篇 |
1994年 | 528篇 |
1993年 | 436篇 |
1992年 | 433篇 |
1991年 | 397篇 |
1990年 | 348篇 |
1989年 | 303篇 |
1988年 | 56篇 |
1987年 | 48篇 |
1986年 | 23篇 |
1985年 | 20篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1959年 | 4篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Daniel FRANCO Gennaro INFANTE Donal O'REGAN 《数学学报(英文版)》2006,22(6):1745-1750
We establish new criteria for the existence of either positive or nonzero solutions of the Urysohn integral equation. We also discuss the existence of an interval of positive eigenvalues and sufficient conditions for the existence of at least a positive eigenvalue with a nonzero or positive eigenfunction for the Urysohn integral operator. Among others, we employ techniques based on fixed point index theory for compact maps, which are new for this type of equation. 相似文献
82.
Ling-yan Tang Song-he Song 《应用数学学报(英文版)》2007,23(2):303-310
In this paper,we use Daubechies scaling functions as test functions for the Galerkin method,and discuss Wavelet-Galerkin solutions for the Hamilton-Jacobi equations.It can be proved that the schemesare TVD schemes.Numerical tests indicate that the schemes are suitable for the Hamilton-Jacobi equations.Furthermore,they have high-order accuracy in smooth regions and good resolution of singularities. 相似文献
83.
脉冲中立型时滞抛物方程的振动性 总被引:6,自引:0,他引:6
本文研究了一类脉冲中立型时滞抛物方程解的振动性及强振动性,获得了此类脉冲中立型时滞抛物方程解振动和强振动的代数判据. 相似文献
84.
Bound States of the S-Wave Equation with Equal Scalar and Vector Standard Eckart Potential 下载免费PDF全文
Eser Olgar Ramazan Koc Hayriye Tutunculer 《中国物理快报》2006,23(3):539-541
A supersymmetric technique for the bound-state solutions of the s-wave Klein-Gordon equation with equal scalar and vector standard Eckart-type potential is proposed. Its exact solutions are obtained. Possible generalization of our approach is outlined. 相似文献
85.
A functional equation of nonlinear iterates is discussed on the circle S1 for its continuous solutions and differentiable solutions. By lifting to R, the existence, uniqueness and stability of those solutions are obtained. Techniques of continuation are used to guarantee the preservation of continuity and differentiability in lifting. 相似文献
86.
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
87.
The Darboux transformation of a differential-difference equation associated with a 3 × 3 matrix spectral problem is derived. As an application, explicit soliton solutions of the differential-difference equation are presented. 相似文献
88.
89.
90.