全文获取类型
收费全文 | 138篇 |
免费 | 4篇 |
国内免费 | 15篇 |
专业分类
电工技术 | 14篇 |
综合类 | 23篇 |
化学工业 | 9篇 |
金属工艺 | 2篇 |
机械仪表 | 2篇 |
建筑科学 | 8篇 |
矿业工程 | 1篇 |
能源动力 | 24篇 |
轻工业 | 3篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 19篇 |
一般工业技术 | 12篇 |
原子能技术 | 1篇 |
自动化技术 | 37篇 |
出版年
2023年 | 10篇 |
2022年 | 1篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 6篇 |
2017年 | 14篇 |
2016年 | 13篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 6篇 |
2012年 | 11篇 |
2011年 | 7篇 |
2010年 | 11篇 |
2009年 | 8篇 |
2008年 | 6篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1993年 | 3篇 |
1982年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 171 毫秒
1.
《Composites Part B》2007,38(5-6):509-522
Recent world events such as bombings in London, Madrid and Istanbul have highlighted the susceptibility of many civilian structures to terrorist attack. Explosives directed towards vulnerable structures may cause considerable damage and loss of life. As a result, there is now a desire to increase the blast resistance of many types of existing structures. This has led to experimental and finite element (FE) research in retrofitting concrete and masonry structures with fibre reinforced polymer (FRP) composites for blast protection. This paper presents a review of the publicly available literature and highlights areas where research is lacking. 相似文献
2.
3.
《Catalysis communications》2007,8(11):1578-1582
In situ generation of H2O2 with high yield can be accomplished by reacting O2 with NH2OH from hydroxylammonium salt [NH2OH · HCl or (NH2OH)2 · H2SO4] in a neutral aqueous medium using a reusable heterogeneous Pd (1.0 wt%)/Al2O3 catalyst, even at low temperature (10 °C), with the formation of harmless by-products (viz. N2 and water). The presence of KCl or KBr in the medium has beneficial effect. The H2O2 generation is strongly influenced by the pH of medium, reaction period and temperature; best results are obtained at the optimum pH and reaction medium. 相似文献
4.
基于EFDC模型和WASP模型建立了深圳河湾水动力和水质模型,采用2011年实测数据对模型进行率定和验证,结果表明,计算值与实测值吻合较好,丰枯季高低潮位平均误差小于0.20 m,DO、BOD5平均误差小于20%,TN、TP和Chl a(叶绿素a)平均误差小于30%。在此基础上进行案例研究,研究结果表明,氮、磷营养盐负荷削减80%对藻类生长的影响不明显;削减95%负荷时,Chl a浓度下降40%。 相似文献
5.
We propose a biologically-motivated computational model for learning task-driven and object-based visual attention control in interactive environments. In this model, top-down attention is learned interactively and is used to search for a desired object in the scene through biasing the bottom-up attention in order to form a need-based and object-driven state representation of the environment. Our model consists of three layers. First, in the early visual processing layer, most salient location of a scene is derived using the biased saliency-based bottom-up model of visual attention. Then a cognitive component in the higher visual processing layer performs an application specific operation like object recognition at the focus of attention. From this information, a state is derived in the decision making and learning layer. Top-down attention is learned by the U-TREE algorithm which successively grows an object-based binary tree. Internal nodes in this tree check the existence of a specific object in the scene by biasing the early vision and the object recognition parts. Its leaves point to states in the action value table. Motor actions are associated with the leaves. After performing a motor action, the agent receives a reinforcement signal from the critic. This signal is alternately used for modifying the tree or updating the action selection policy. The proposed model is evaluated on visual navigation tasks, where obtained results lend support to the applicability and usefulness of the developed method for robotics. 相似文献
7.
8.
The Semantic Web and ontologies have received increased attention in recent years. The delivery of well-designed ontologies enhances the effect of Semantic Web services, but building ontologies from scratch requires considerable time and effort. Modularizing ontologies and integrating ontology modules to a given context help users effectively develop ontologies and revitalize ontology dissemination. Therefore, various tools for modularizing ontologies have been developed. However, selecting an appropriate tool to fit a given context is difficult because the assumptions for the approaches greatly vary. Therefore, a suitable framework is required to compare and help screen the most suitable modularization tool.In this research, we propose a new evaluation framework for selecting an appropriate ontology modularization tool. We present three aspects of tool evaluation as the main dimensions for the assessment of modularization tools: tool performance, data performance, and usability.This study provides an implicit evaluation and an empirical analysis of three modularization tools. It also provides an evaluation method for ontology modularization, enabling ontology engineers to compare different modularization tools and easily choose an appropriate one for the production of qualifying ontology modules.The experimental results indicate that the proposed evaluation criteria for ontology modularization tools are valid and effective. This research provides a useful method for assessing and selecting ontology modularization tools. Modularization performance, data performance, and usability are the three modularization aspects designed and applied to the context of ontology. We provide a new focus on the comprehensive framework to evaluate the performance and usability of ontology modularization tools. The proposed framework should be of value to both ontology engineers, who are interested in ontology modularization, and to practitioners, who need information on how to evaluate and select a specific type of ontology tool in accordance with the requirements of the individual environment. 相似文献
9.
基于MPSK信号的非线性频偏估计算法,通过对叠加了高斯分布白噪声接收信号的非线性交换分析,将非线性滤波(中值滤波)算法应用于载波频率估计之中.运用Monte Carlo仿真手段对其进行了验证,结果表明,在非线性频率估计中运用中值滤波算法后,其估计的均方误差较之运用均值滤波算法有很大的改善. 相似文献
10.
Two new 2D-conjugated D-A copolymers, PBDTT-S-DPP and PBDTSe-S-DPP, based on benzodithiophene (BDT) donor unit with alkylthio-thiophene or alkylthio-selenophene conjugated side chains and 2,5-bis(2-butyloctyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione) (DPP) acceptor unit, were synthesized for the application as donor materials in polymer solar cells (PSCs). The two polymers were characterized by absorption spectroscopy, cyclic voltammetry, thermogravimetric analysis, theoretical calculation with density functional theory, X-ray diffraction and photovoltaic measurements. The results show that the alkylthio-thiophene/selenophene side groups on BDT unit and intramolecular hydrogen bonding interaction in DPP acceptor unit play important roles in affecting the absorption, HOMO energy levels, molecular planarity and the crystallinity of the polymers. The PSCs based on PBDTT-S-DPP or PBDTSe-S-DPP as donor and PC71BM as acceptor demonstrate power conversion efficiency (PCE) of 5.62% and 5.01%, with relatively higher Voc of 0.79 V and 0.76 V, respectively. 相似文献