全文获取类型
收费全文 | 82838篇 |
免费 | 585篇 |
国内免费 | 406篇 |
专业分类
化学 | 27214篇 |
晶体学 | 809篇 |
力学 | 6879篇 |
数学 | 32966篇 |
物理学 | 15961篇 |
出版年
2023年 | 54篇 |
2022年 | 52篇 |
2021年 | 161篇 |
2020年 | 156篇 |
2019年 | 154篇 |
2018年 | 10497篇 |
2017年 | 10315篇 |
2016年 | 6273篇 |
2015年 | 1055篇 |
2014年 | 518篇 |
2013年 | 626篇 |
2012年 | 4145篇 |
2011年 | 10895篇 |
2010年 | 5855篇 |
2009年 | 6238篇 |
2008年 | 6913篇 |
2007年 | 9028篇 |
2006年 | 506篇 |
2005年 | 1576篇 |
2004年 | 1734篇 |
2003年 | 2119篇 |
2002年 | 1146篇 |
2001年 | 289篇 |
2000年 | 316篇 |
1999年 | 193篇 |
1998年 | 230篇 |
1997年 | 196篇 |
1996年 | 233篇 |
1995年 | 160篇 |
1994年 | 119篇 |
1993年 | 123篇 |
1992年 | 77篇 |
1991年 | 90篇 |
1990年 | 69篇 |
1989年 | 75篇 |
1988年 | 80篇 |
1987年 | 81篇 |
1986年 | 75篇 |
1985年 | 71篇 |
1984年 | 64篇 |
1983年 | 49篇 |
1982年 | 63篇 |
1981年 | 50篇 |
1980年 | 60篇 |
1979年 | 58篇 |
1978年 | 49篇 |
1914年 | 45篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Nonlinear Dynamics - A new model-free robust control scheme for payload swing angle attenuation of two-dimensional crane systems with varying rope length is introduced in this work. The proposed... 相似文献
4.
Cardin Pedro Toniol Teixeira Marco Antonio 《Journal of Dynamics and Differential Equations》2022,34(2):775-787
Journal of Dynamics and Differential Equations - In this paper we focus on a class of symmetric vector fields in the context of singularly perturbed fast-slow dynamical systems. Our main question... 相似文献
5.
Application of TiO2-nanotubes/PbO2 as an anode for the electrochemical elimination of Acid Red 1 dye
Santos José Eudes L. de Moura Dayanne Chianca da Silva Djalma Ribeiro Panizza Marco Martínez-Huitle Carlos A. 《Journal of Solid State Electrochemistry》2019,23(2):351-360
Journal of Solid State Electrochemistry - In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an... 相似文献
6.
7.
Yuliang Zhao 《中国科学:化学(英文版)》2018,61(12):1481-1482
正Living organisms have developed their unique strategies during the natural evolution for building hard tissues with minerals, including silica, calcium carbonate, calcium phosphate, and ferric oxide [1]. Such biomineralized materials generally have complex hierarchical structures with excellent mechanical properties. Although bioinspired approaches have led to the creation of well-defined synthetic structural materials ranging from micro to macro scales, the rational design of discrete biomimetic structures at the nanoscale remains a grand challenge. 相似文献
8.
JuHong Ge 《Nonlinear dynamics》2018,94(1):87-98
A five-neuron network model with multiple delays is proposed. This paper presents the combined effect of different delays on the dynamics of the proposed network. Pitchfork bifurcation is discussed in detail with the variation of the value of coupled weight or attenuation rate of internal neurons. By analyzing the corresponding characteristic equation, some stable criteria on delay-dependence and delay-independence are derived including multiple delays and coupled weights and the periodic oscillation arises bifurcated from the trivial equilibrium after the network loses its stability. Stable regions on delay-dependence are displayed in the two delayed parameter plane. It is shown that multiple delays can produce stability switching between resting state and periodic activity. Finally, theoretical results are justified by providing two illustrative examples. 相似文献
9.
It is shown that the countably infinite dimensional pointed vector space (the vector space equipped with a constant) over a finite field has infinitely many first order definable reducts. This implies that the countable homogeneous Boolean-algebra has infinitely many reducts. 相似文献
10.