全文获取类型
收费全文 | 38149篇 |
免费 | 4859篇 |
国内免费 | 3166篇 |
专业分类
电工技术 | 9390篇 |
综合类 | 4761篇 |
化学工业 | 1440篇 |
金属工艺 | 733篇 |
机械仪表 | 2399篇 |
建筑科学 | 2061篇 |
矿业工程 | 721篇 |
能源动力 | 844篇 |
轻工业 | 265篇 |
水利工程 | 584篇 |
石油天然气 | 470篇 |
武器工业 | 421篇 |
无线电 | 9092篇 |
一般工业技术 | 3287篇 |
冶金工业 | 471篇 |
原子能技术 | 341篇 |
自动化技术 | 8894篇 |
出版年
2024年 | 194篇 |
2023年 | 491篇 |
2022年 | 674篇 |
2021年 | 848篇 |
2020年 | 1131篇 |
2019年 | 983篇 |
2018年 | 927篇 |
2017年 | 1318篇 |
2016年 | 1504篇 |
2015年 | 1484篇 |
2014年 | 2263篇 |
2013年 | 2487篇 |
2012年 | 2849篇 |
2011年 | 2926篇 |
2010年 | 2253篇 |
2009年 | 2334篇 |
2008年 | 2431篇 |
2007年 | 2863篇 |
2006年 | 2484篇 |
2005年 | 2143篇 |
2004年 | 1823篇 |
2003年 | 1581篇 |
2002年 | 1277篇 |
2001年 | 1207篇 |
2000年 | 1095篇 |
1999年 | 815篇 |
1998年 | 621篇 |
1997年 | 619篇 |
1996年 | 517篇 |
1995年 | 419篇 |
1994年 | 372篇 |
1993年 | 264篇 |
1992年 | 240篇 |
1991年 | 176篇 |
1990年 | 137篇 |
1989年 | 115篇 |
1988年 | 90篇 |
1987年 | 33篇 |
1986年 | 25篇 |
1985年 | 20篇 |
1984年 | 31篇 |
1983年 | 14篇 |
1982年 | 18篇 |
1981年 | 13篇 |
1980年 | 18篇 |
1979年 | 14篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1976年 | 2篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
基于MATLAB在化工优化设计中的应用 总被引:2,自引:0,他引:2
结合化工优化计算的实例,着重介绍如何应用MATLAB7.0提供的优化工具箱来对线性规划及非线性规划模型进行求解。 相似文献
62.
GAO Qinglu~ WU Bo~ GUO Guang~ .School of Management Wuhan University of Technology Wuhan China .School of Mechanical Engineering Huazhong University of Science Technology Wuhan China 《武汉理工大学学报》2006,28(Z2)
This article puts forward a scheduling method for nonlinear process plan shop floor.Task allocation and load bal- ance are realized by bidding mechanism.Though the agent interaction process,the execution of tasks is determined and the coherence of manufacturing decision is verified.The employment of heuristic index can help to optimize the system performance. 相似文献
63.
Kernel Spectral Matched Filter for Hyperspectral Imagery 总被引:1,自引:0,他引:1
In this paper a kernel-based nonlinear spectral matched filter is introduced for target detection in hyperspectral imagery,
which is implemented by using the ideas in kernel-based learning theory. A spectral matched filter is defined in a feature
space of high dimensionality, which is implicitly generated by a nonlinear mapping associated with a kernel function. A kernel
version of the matched filter is derived by expressing the spectral matched filter in terms of the vector dot products form
and replacing each dot product with a kernel function using the so called kernel trick property of the Mercer kernels. The proposed kernel spectral matched filter is equivalent to a nonlinear matched filter in the original input space,
which is capable of generating nonlinear decision boundaries. The kernel version of the linear spectral matched filter is
implemented and simulation results on hyperspectral imagery show that the kernel spectral matched filter outperforms the conventional
linear matched filter. 相似文献
64.
用Tow-Thomas电路设计含有限非零传输零点有源滤波器的方法 总被引:4,自引:1,他引:3
Tow-Thomas电路是一种实现全极点滤波器的典型电路。本文给出了用Tow-Thoms电路设计含有限非零传输零点有源滤波器的方法,从而使Tow-Thomas电路可用于单片集成滤波器电路。而文中给出的公式可用于计算外接元件。设计实例表明了文中给出的计算公式的正确性。 相似文献
65.
66.
D. A. Gubaidullin R. G. Zaripov R. G. Galiullin E. R. Galiullina L. A. Tkachenko 《High Temperature》2004,42(5):794-802
Nonlinear oscillation of aerosol in the vicinity of a resonance frequency that is twice lower than the first eigenfrequency (subharmonic resonance) is experimentally investigated in tubes with different conditions at the ends. The time dependence of the number density of aerosol droplets is determined, and the effect of the frequency and intensity of oscillation on the process of coagulation of droplets is studied. The nonmonotonic pattern of the dependence of the time of coagulation of aerosol droplets on the frequency of excitation with a minimal value at resonance is found. Ordered space-time structures (alternation of denser and looser regions of aerosol) are revealed in the visible region in the vicinity of the middle of a closed tube. 相似文献
67.
68.
对称非线性系统的无交互控制 总被引:1,自引:0,他引:1
本文讨论了具有对称性的非线性系统的无交互控制问题。通过定义对称系统的导出分布族的新概念,我们得出了问题可解的条件。我们取得的结果较不具对称性的情况要简单一些。从而说明,对称性不仅使得系统具有较好的结构,而且使得它的其它一些问题的研究得到简化。 相似文献
69.
E. I. Mashinskii 《Journal of Mining Science》2003,39(1):8-14
Using the theory of microplasticity as the base, it is shown that the curvature of graph for the function describing the equation of state of rocks can change its sign depending on the value of the mechanical energy applied. The experiments on dolomites under the strains of order of 10-6 reveal an increase in wave velocities as the amplitude grows. 相似文献
70.
After considering the stabilization of a specific class of stochastic nonlinear systems in a companion paper, in this second part, we address the classical question of when is a stabilizing (in probability) controller optimal and show that for every system with a stochastic control Lyapunov function it is possible to construct a controller which is optimal with respect to a meaningful cost functional. Then we return to the problem from Part I and design an optimal backstepping controller whose cost functional includes penalty on control effort and which has an infinite gain margin. 相似文献