全文获取类型
收费全文 | 940篇 |
免费 | 85篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 16篇 |
综合类 | 3篇 |
化学工业 | 197篇 |
金属工艺 | 26篇 |
机械仪表 | 43篇 |
建筑科学 | 31篇 |
能源动力 | 53篇 |
轻工业 | 102篇 |
水利工程 | 6篇 |
石油天然气 | 1篇 |
无线电 | 147篇 |
一般工业技术 | 221篇 |
冶金工业 | 70篇 |
原子能技术 | 3篇 |
自动化技术 | 107篇 |
出版年
2023年 | 14篇 |
2022年 | 8篇 |
2021年 | 20篇 |
2020年 | 23篇 |
2019年 | 36篇 |
2018年 | 24篇 |
2017年 | 47篇 |
2016年 | 33篇 |
2015年 | 44篇 |
2014年 | 60篇 |
2013年 | 69篇 |
2012年 | 72篇 |
2011年 | 93篇 |
2010年 | 60篇 |
2009年 | 58篇 |
2008年 | 50篇 |
2007年 | 41篇 |
2006年 | 33篇 |
2005年 | 24篇 |
2004年 | 15篇 |
2003年 | 18篇 |
2002年 | 10篇 |
2001年 | 15篇 |
2000年 | 12篇 |
1999年 | 12篇 |
1998年 | 27篇 |
1997年 | 15篇 |
1996年 | 18篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 9篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有1026条查询结果,搜索用时 31 毫秒
21.
Seog‐Young Lee Mi‐Yeon Lee Won‐Yeol Choi Dong‐Heon Lee Yong‐Seog Kim 《Journal of the Society for Information Display》2008,16(12):1219-1227
Abstract— In an attempt to reduce materials and processing costs of ACPDPs, aluminum fence electrodes were prepared on soda‐lime glass substrates by chemically etching aluminum foil bonded directly onto the substrate via an anodic‐bonding process. Several different fence‐electrode patterns were designed and coated either with a glass dielectric layer or with an anodic aluminum oxide layer. Firing voltages, operation margin, luminance, and luminous efficiency of such test panels were evaluated. The results indicated that the performance of test panels with aluminum fence electrodes is comparable with conventional test panels with ITO/Ag electrodes, demonstrating the possibility of a dramatic reduction in the costs of ACPDPs. 相似文献
22.
ManyEyes: a site for visualization at internet scale 总被引:1,自引:0,他引:1
Viegas FB Wattenberg M van Ham F Kriss J McKeon M 《IEEE transactions on visualization and computer graphics》2007,13(6):1121-1128
We describe the design and deployment of Many Eyes, a public web site where users may upload data, create interactive visualizations, and carry on discussions. The goal of the site is to support collaboration around visualizations at a large scale by fostering a social style of data analysis in which visualizations not only serve as a discovery tool for individuals but also as a medium to spur discussion among users. To support this goal, the site includes novel mechanisms for end-user creation of visualizations and asynchronous collaboration around those visualizations. In addition to describing these technologies, we provide a preliminary report on the activity of our users. 相似文献
23.
Heon M Carrier C Cadorette J Richard P Rouleau D Rodrigue S Lecomte R 《IEEE transactions on medical imaging》1993,12(2):293-298
A stationary sampling scheme applicable to tomographic instruments incorporating two or more detector layers is described and tested. In this concept, the detectors in adjacent layers are angularly offset by half the interdetector distance. By reconstructing in one single slice all lines of response defined by two adjacent rings of detectors, a fourfold increase in the number of coincidence lines is obtained and a uniform sampling distance equal to one-quarter the interdetector spacing is achieved. Whereas this is obtained at the expense of a 100% degradation of the resolution in the axial direction, with the recent breed of PET (positron emission tomography) scanners using nearly square cross section detectors, the resolution loss may be tolerable in many situations. In addition, normal reconstruction of the individual coincidence planes is always possible. The sampling concept was investigated experimentally with the help of the Universite de Sherbrooke PET camera simulator. 相似文献
24.
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
25.
Database summarization using fuzzy ISA hierarchies 总被引:3,自引:0,他引:3
Do Heon Lee Myoung Ho Kim 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》1997,27(1):68-78
Summary discovery is one of the major components of knowledge discovery in databases, which provides the user with comprehensive information for grasping the essence from a large amount of information in a database. We propose an interactive top down summary discovery process which utilizes fuzzy ISA hierarchies as domain knowledge. We define a generalized tuple as a representational form of a database summary including fuzzy concepts. By virtue of fuzzy ISA hierarchies where fuzzy ISA relationships common in actual domains are naturally expressed, the discovery process comes up with more accurate database summaries. We also present an informativeness measure for distinguishing generalized tuples that delivers much information to users, based on C. Shannon's (1948) information theory. 相似文献
26.
During the solidification of the AZ91D-alloys, the Al8(Mn, Fe)5 phase is generally precipitated in the melt in advance of the precipitation of the primary α-Mg. The basic principle for manufacturing AZ91D-alloy slurries for semi solid forming is to use the Al8(Mn, Fe)5 precipitates as the heterogeneous nucleation sites for primary α-Mg phases. Microscopic analysis for the location of the Al8(Mn, Fe)5 precipitate explains that the Al8(Mn, Fe)5 precipitate is the effective heterogeneous nucleation site for the primary α-Mg phase. It was also observed that increase of the Mn content in the melt and the cooling rate below to the solid/liquid two-phase region resulted in smaller and more globular primary α-Mg due to the increase of heterogeneous nucleation sites. It was found that the average α-Mg diameter grew as a function of t0.278, where t is the holding time at the solid/liquid two-phase region. This would be attributed to the Ostwald type ripening and coalescence between primary α-Mg phases. The cooling rate below to the solid/liquid two-phase region, Mn content in AZ91D alloy, and the holding time and temperature affected on the quality of slurry. 相似文献
27.
Hyung-il Moon Young-eun Jeon Dae-Young Kim Heon Young Kim Yong-soo Kim 《Journal of Mechanical Science and Technology》2012,26(8):2595-2601
This paper describes the design process for an automobile crumple zone for pedestrian protection. The impact load and bending moments predicted by impact analysis were used to design a plastic structure that may help reduce pedestrian injuries to the thigh area. The fracture effect was incorporated into the model by calculating the damage to the plastic material during impact, and the analysis was conducted under the European New Car Assessment Program (Euro NCAP) test conditions, using the upper legform developed by ESI Corporation. In addition, the values predicted by the analysis were validated by comparison with results of actual impact tests. 相似文献
28.
Jeongseok Oh Seokswoo Cho Bumsik Ham 《Journal of Mechanical Science and Technology》2017,31(12):5761-5767
In a polyethylene boat, a transom pod is subjected to repeated thrust forces generated by an outboard motor. The structural design of the transom pod for the outboard motor must be considered because it is subjected to cyclic bending moments causing thrust forces of the outboard motor. We designed a transom pod reinforced with aluminum alloy plate inside the transom pod in a polyethylene boat and obtained an optimal thickness of the Al alloy plate to ensure the transom pod durability. We then performed a structural analysis for the transom pod reinforced with Al alloy plate and estimated the fatigue life using modified Goodman diagram. The optimal thickness of Al alloy plate was 7 mm. 相似文献
29.
30.
Sanne Boschman Reinout Kleinhans Maarten van Ham 《Journal of Housing and the Built Environment》2017,32(3):495-512
Selective mobility into and out of urban neighbourhoods is one of the main driving forces of segregation. Earlier research has found group differences in who wants to leave or who leaves certain types of neighbourhoods. A factor that has received little attention so far is that some residents will have a desire to leave their neighbourhood, but are unable to do so. If there are differences between population groups in the realisation of desires to leave the neighbourhood, this might lead to involuntary segregation. This paper uses a unique combination of register data and survey data. We combine data from a large housing survey in the Netherlands (WoON) with longitudinal register data from the Netherlands (SSD) which contains individual-level information on residential mobility histories. This allows us to study whether households with a desire to leave their neighbourhood do realise this desire and which households are successful in leaving which neighbourhoods. A more thorough insight in who wants to leave which neighbourhoods but is unable to do so will contribute to a better understanding of selective mobility and segregation. We find that ethnic minorities and low-income households are less likely to realise a desire to leave their neighbourhood. We expected that ethnic minorities would be especially unsuccessful in realising desires to leave minority concentration neighbourhoods; however, for none of the ethnic groups we found an effect of neighbourhood ethnic composition on the realisation of desires to leave. 相似文献