全文获取类型
收费全文 | 493篇 |
免费 | 10篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 96篇 |
金属工艺 | 6篇 |
机械仪表 | 10篇 |
建筑科学 | 15篇 |
能源动力 | 28篇 |
轻工业 | 34篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 61篇 |
一般工业技术 | 69篇 |
冶金工业 | 99篇 |
原子能技术 | 4篇 |
自动化技术 | 75篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 15篇 |
2012年 | 16篇 |
2011年 | 24篇 |
2010年 | 21篇 |
2009年 | 17篇 |
2008年 | 20篇 |
2007年 | 16篇 |
2006年 | 17篇 |
2005年 | 6篇 |
2004年 | 15篇 |
2003年 | 13篇 |
2002年 | 17篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 31篇 |
1997年 | 21篇 |
1996年 | 14篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 17篇 |
1992年 | 5篇 |
1991年 | 9篇 |
1990年 | 11篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1969年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有503条查询结果,搜索用时 15 毫秒
1.
Guest Editorial: Wireless Mobile Internet 总被引:1,自引:0,他引:1
2.
3.
William Fornaciari Donatella Sciuto Cristina Silvano Vittorio Zaccaria 《Design Automation for Embedded Systems》2002,7(1-2):7-33
In this paper, we propose a system-level design methodology for the efficient exploration of the architectural parameters of the memory sub-systems, from the energy-delay joint perspective. The aim is to find the best configuration of the memory hierarchy without performing the exhaustive analysis of the parameters space. The target system architecture includes the processor, separated instruction and data caches, the main memory, and the system buses. To achieve a fast convergence toward the near-optimal configuration, the proposed methodology adopts an iterative local-search algorithm based on the sensitivity analysis of the cost function with respect to the tuning parameters of the memory sub-system architecture. The exploration strategy is based on the Energy-Delay Product (EDP) metric taking into consideration both performance and energy constraints. The effectiveness of the proposed methodology has been demonstrated through the design space exploration of a real-world case study: the optimization of the memory hierarchy of a MicroSPARC2-based system executing the set of Mediabench benchmarks for multimedia applications. Experimental results have shown an optimization speedup of 2 orders of magnitude with respect to the full search approach, while the near-optimal system-level configuration is characterized by a distance from the optimal full search configuration in the range of 2%. 相似文献
4.
5.
Biodiesel has become an attractive diesel fuel substitute due to its environmental benefits since it can be made from renewable resource. However, the high costs surrounding biodiesel production remains the main problem in making it competitive in the fuel market either as a blend or as a neat fuel. More than 80% of the production cost is associated with the feedstock itself and consequently, efforts are focused on developing technologies capable of using lower-cost feedstocks, such as recycled cooking oils and wastes from animal or vegetable oil processing operations. 相似文献
6.
Multiresidue method for pesticides in drinking water using a graphitized carbon black cartridge extraction and liquid chromatographic analysis 总被引:2,自引:0,他引:2
A general liquid-solid extraction procedure for the isolation of pesticides from groundwater and drinking water for high-performance liquid chromatography (HPLC) is presented. This simple and rapid procedure involved passing a 2-L sample through a 250-mg graphitized carbon black (Carbopack B) cartridge at a flow rate of 150-160 mL/min. By taking advantage of the presence of positively charged active centers on the Carbopack B surface, a stepwise elution system allowed the complete separation of base-neutral pesticides from acidic ones. After partial solvent removal, the components in the two fractions were separated and quantified by gradient elution, reversed-phase HPLC with ultraviolet (UV) detection. The performance of the Carbopack cartridge was compared with that of a 500-mg C-18 bonded silica cartridge. With the Carbopack cartridge, the grand mean measurement accuracy of the 35 pesticides considered was 95%. With the C-18 cartridge, the grand mean measurement accuracy of the analytes was 76%. Compared to the C-18 cartridge, additional advantages of using a Carbopack cartridge are that the extraction procedure is about 7 times shorter, no pH adjustment of the environmental sample is necessary for trapping acidic compounds, and one cartridge instead of two suffices to extract base-neutral and acidic pesticides, making the Carbopack cartridge more adaptable than the C-18 one for field use. The detection limits by this method of all the pesticides considered were between 0.003 and 0.07 micrograms/L. 相似文献
7.
Leonardo Badia Andrea Baiocchi Alfredo Todini Simone Merlin Silvano Pupolin Andrea Zanella Michele Zorzi 《Wireless Communications, IEEE》2007,14(1):36-43
Multicellular networks based on the IEEE 802.16 standard appear to be very promising candidates to provide end users with broadband wireless access. However, they also pose interesting challenges in terms of radio resource management, where several design choices are not specified in the standard, intentionally left open to implementors. For this reason, we focus in this article on scheduling and resource allocation, and investigate how they could operate in a cross-layer fashion. In particular, we describe the principles of joint scheduling and resource allocation for IEEE 802.16 operating in AMC mode, and discuss the critical role played by physical layer considerations, especially intercell interference estimation and channel state awareness, in the obtained performance. This leads to identifying key open issues and possible general solutions 相似文献
8.
The usual laser rate equations have been applied to fit energy and shape of pulsed emissions of RF CO2 single mode lasers starting from the discharge and cavity parameters. The model well reproduce the laser behaviour, if to fit the turn-off normally observed in these lasers we introduce a phase laser gain correction related to the frequency chirp. 相似文献
9.
Silvano Dal Zilio Denis Lugiez 《Applicable Algebra in Engineering, Communication and Computing》2006,17(5):337-377
XML documents may be roughly described as unranked, ordered trees and it is therefore natural to use tree automata to process or validate them. This idea has already been successfully applied in the context of Document Type Definition (DTD), the simplest standard for defining document validity, but additional work is needed to take into account XML Schema, a more advanced standard, for which regular tree automata are not satisfactory. In this paper, we introduce Sheaves Logic (SL), a new tree logic that extends the syntax of the – recursion-free fragment of – W3C XML Schema Definition Language (WXS). Then, we define a new class of automata for unranked trees that provides decision procedures for the basic questions about SL: model-checking; satisfiability; entailment. The same class of automata is also used to answer basic questions about WXS, including recursive schemas: decidability of type-checking documents; testing the emptiness of schemas; testing that a schema subsumes another one.This work was partially supported by the French government research grant ACI TRALALA and by IST Global Computing Profundis. 相似文献
10.