全文获取类型
收费全文 | 2855篇 |
免费 | 209篇 |
国内免费 | 23篇 |
专业分类
化学 | 1966篇 |
晶体学 | 31篇 |
力学 | 104篇 |
数学 | 367篇 |
物理学 | 619篇 |
出版年
2024年 | 8篇 |
2023年 | 26篇 |
2022年 | 73篇 |
2021年 | 154篇 |
2020年 | 89篇 |
2019年 | 126篇 |
2018年 | 110篇 |
2017年 | 80篇 |
2016年 | 179篇 |
2015年 | 133篇 |
2014年 | 152篇 |
2013年 | 212篇 |
2012年 | 198篇 |
2011年 | 168篇 |
2010年 | 121篇 |
2009年 | 114篇 |
2008年 | 137篇 |
2007年 | 142篇 |
2006年 | 118篇 |
2005年 | 87篇 |
2004年 | 77篇 |
2003年 | 63篇 |
2002年 | 63篇 |
2001年 | 53篇 |
2000年 | 37篇 |
1999年 | 30篇 |
1998年 | 13篇 |
1997年 | 15篇 |
1996年 | 14篇 |
1995年 | 16篇 |
1994年 | 12篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1990年 | 16篇 |
1988年 | 9篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 21篇 |
1983年 | 9篇 |
1981年 | 16篇 |
1980年 | 19篇 |
1979年 | 8篇 |
1978年 | 11篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1973年 | 6篇 |
1971年 | 6篇 |
1862年 | 8篇 |
排序方式: 共有3087条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
The main result of the paper is a theorem, using which a new proof of Roth’s theorem is obtained, a new solvability criterion
for the matrix equation AX-YB = C is proved, a formula for a particular solution of the latter is derived, and the least of
the orders of square nonsingular matrices containing a given rectangular matrix as a submatrix is determined. Bibliography:
5 titles.
__________
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 323, 2005, pp. 15–23. 相似文献
7.
Al.Th. Kermanidis D.G. Stamatelos G.N. Labeas Sp.G. Pantelakis 《Theoretical and Applied Fracture Mechanics》2006,45(2):148-158
The synergetic effect of corrosion and corrosion induced hydrogen embrittlement damage processes which occur at local scale has been found to result in a dramatic macroscopic tensile ductility loss of the 2024 aluminum alloy. In the present work, the tensile behaviour of corroded 2024 T351 specimens has been estimated on the basis of FE analysis by taking into account the local material properties in the damaged areas. A parametric study is involved to account for the effect of thickness in the results. Calculated tensile properties obtained with the analysis agree well with experimental data. 相似文献
8.
A new type of optoelectronic cellular neural network has been developed by providing the capability of coefficients adjusment of cellular neural network (CNN) using Widrow based perceptron learning algorithm. The new supervised cellular neural network is called Widrow-CNN. Despite the unsupervised CNN, the proposed learning algorithm allows to use the Widrow-CNN for various image processing applications easily. Also, the capability of CNN for image processing and feature extraction has been improved using basic joint transform correlation architecture. This hardware application presents high speed processing capability compared to digital applications. The optoelectronic Widrow-CNN has been tested for classic CNN feature extraction problems. It yields the best results even in case of hard feature extraction problems such as diagonal line detection and vertical line determination. 相似文献
9.
L. V. Giurgiu M. N. Grecu X. Filip O. Raita Al. Darabont D. Gavre J. Blasco 《Applied magnetic resonance》2003,24(3-4):351-360
We report an electron paramagnetic resonance (EPR) investigation of the spin dynamics in the paramagnetic regime of the colossal magnetoresistive manganites La2/3Ca1/3Mn1?x Me x O3 (Me=Al, In;x≤0.05). The temperature dependences of the EPR linewidth and integral intensity have been analyzed in terms of the bottleneck spin relaxation and small-polaron hopping models. The exchange coupling integral between Mn3+ and Mn4+ ions and the polaron activation energy decrease with increasing doping level. A discussion is given concerning the factors which could explain the observed changes. 相似文献
10.