全文获取类型
收费全文 | 1304篇 |
免费 | 100篇 |
国内免费 | 97篇 |
专业分类
电工技术 | 78篇 |
综合类 | 52篇 |
化学工业 | 227篇 |
金属工艺 | 70篇 |
机械仪表 | 103篇 |
建筑科学 | 125篇 |
矿业工程 | 41篇 |
能源动力 | 34篇 |
轻工业 | 48篇 |
水利工程 | 23篇 |
石油天然气 | 104篇 |
武器工业 | 5篇 |
无线电 | 132篇 |
一般工业技术 | 145篇 |
冶金工业 | 40篇 |
原子能技术 | 14篇 |
自动化技术 | 260篇 |
出版年
2024年 | 7篇 |
2023年 | 24篇 |
2022年 | 26篇 |
2021年 | 62篇 |
2020年 | 49篇 |
2019年 | 32篇 |
2018年 | 35篇 |
2017年 | 49篇 |
2016年 | 45篇 |
2015年 | 52篇 |
2014年 | 60篇 |
2013年 | 93篇 |
2012年 | 74篇 |
2011年 | 103篇 |
2010年 | 77篇 |
2009年 | 92篇 |
2008年 | 84篇 |
2007年 | 87篇 |
2006年 | 83篇 |
2005年 | 53篇 |
2004年 | 44篇 |
2003年 | 31篇 |
2002年 | 29篇 |
2001年 | 27篇 |
2000年 | 32篇 |
1999年 | 24篇 |
1998年 | 28篇 |
1997年 | 23篇 |
1996年 | 17篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有1501条查询结果,搜索用时 0 毫秒
101.
乘改革开放春风开拓燃机安装市场 总被引:1,自引:0,他引:1
以天然气或柴油为燃料的燃气-蒸汽联合循环发电技术具有热效率高,对环境污染小的突出优点,央国内外建设燃机电厂逐年呈上升之势。文章总结了武汉电力燃机安装有限公司秉发放的春风,开辟国内燃机安装市场的发展道路,为优质、高速地建设燃机电站,争取早日打入国际市场提供了富贵的经验。 相似文献
102.
查峰 《计算机应用与软件》2009,26(6):195-197
目前的MCU视频会议主要基于H323标准,适合在专用网内进行部署。设计一种基于SIP的MCU视频会议系统,该系统在软交换网关和MCU分别进行H323和SIP信令互换;呼叫处理部分用标准的SIP信令来实现,业务逻辑用以SIP应用服务器控制,应用服务器与Web服务器间用TCP/IP通信,将会议的媒体处理单元(MCU)、终端、资源管理器、Web服务器有机的结合在一起。 相似文献
103.
Wang JW Wu HN Li HX 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2012,42(3):927-938
In this paper, a distributed fuzzy control design based on Proportional-spatial Derivative (P-sD) is proposed for the exponential stabilization of a class of nonlinear spatially distributed systems described by parabolic partial differential equations (PDEs). Initially, a Takagi-Sugeno (T-S) fuzzy parabolic PDE model is proposed to accurately represent the nonlinear parabolic PDE system. Then, based on the T-S fuzzy PDE model, a novel distributed fuzzy P-sD state feedback controller is developed by combining the PDE theory and the Lyapunov technique, such that the closed-loop PDE system is exponentially stable with a given decay rate. The sufficient condition on the existence of an exponentially stabilizing fuzzy controller is given in terms of a set of spatial differential linear matrix inequalities (SDLMIs). A recursive algorithm based on the finite-difference approximation and the linear matrix inequality (LMI) techniques is also provided to solve these SDLMIs. Finally, the developed design methodology is successfully applied to the feedback control of the Fitz-Hugh-Nagumo equation. 相似文献
104.
本文就CATV网向宽带全业务网升级的策略和技术进行了讨论。首称要将现有CATV网改造为双向传输网。在此基础上,建成CATV广播网和计算机网并行的网络。在计算机网中,应用Cable modem实现数据双向传播,或在CATV网中应用暂时富裕的光纤构成独立计算机网。 相似文献
105.
106.
Yan-Dong Xu Zhen-Yu Zhu Tian-Zhao Xu Hamidreza Abadikhah Jun-Wei Wang Xin Xu Simeon Agathopoulos 《Ceramics International》2018,44(14):16443-16449
Robust hydrophobic surface was produced by modifying the surface of porous Si3N4 membrane, via aminolysis and pyrolysis process, with organosilane-derived inorganic SiNCO nanoparticles, which are tightly adhered to the Si3N4 grains. The resultant material had a high water contact angle of 142°, attributed to -Si-CH3 surface terminal groups and a lotus leaf-like hierarchical structure of the nanoparticles, which had a frame structure with Si-N and Si-O covalent bonds in their bulk. The hydrophobic behavior remained practically unchanged after exposure of the produced membranes to aqueous solutions of humic acid, HCl and NaOH, to benzene, as well as to stirring abrasive slurry with SiC particles, and after exposure at high temperatures, up to 500?°C, to air. The inorganic membrane can be considered for use in a broad range of applications which require robust hydrophobic surfaces. 相似文献
107.
108.
109.
Automatic assembly planning is recognized as an important tool for reducing manufacturing costs in concurrent product and process development. A novel knowledge-based Petri net (KBPN) is defined, based on the incorporation of expert systems into the usual Petri nets, and used for a unified assembly knowledge representation scheme. A KBPN-approach integrated with a sequence generation algorithm is proposed for the modeling, planning, simulation, analysis and evaluation of the flexible assembly system (FAS). The developed KBPN-based assembly planning system (KAPS) can automatically adjust the deviations between the theoretical planning parameters and the process parameters of real assembly operations to guarantee the best strategies and plans (sequences) for flexible assembly. The research findings are exemplified with a simple assembly to show the effectiveness of the method. 相似文献
110.
TheanisotropyfieldHAofPr2 Fe14 Bisabout 30 %higherthanthatofNd2 Fe14 Bwhichresultsinhighin trinsiccoercivityfornanocrystallineexchangecoupledcompositepermanentmagnets .SothePr basedisotropicbondedmagnetshavecurrentlyattractedmuchattentions[1~ 4 ] .Howeverthistypeofpermanentmagnethasnotbeenusedinpractice .Thereexistmagneticinteractionsbetweenadja centgrainseitherinnanocrystallinecompositemagnetsorinanassemblyofsinglehardmagneticphaseofrareearth transitionmetalintermetalliccompounds[5~ 8] … 相似文献