全文获取类型
收费全文 | 2351篇 |
免费 | 129篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 30篇 |
综合类 | 3篇 |
化学工业 | 626篇 |
金属工艺 | 32篇 |
机械仪表 | 77篇 |
建筑科学 | 74篇 |
矿业工程 | 4篇 |
能源动力 | 115篇 |
轻工业 | 266篇 |
水利工程 | 17篇 |
石油天然气 | 9篇 |
无线电 | 191篇 |
一般工业技术 | 396篇 |
冶金工业 | 86篇 |
原子能技术 | 15篇 |
自动化技术 | 546篇 |
出版年
2024年 | 6篇 |
2023年 | 36篇 |
2022年 | 93篇 |
2021年 | 83篇 |
2020年 | 88篇 |
2019年 | 82篇 |
2018年 | 104篇 |
2017年 | 90篇 |
2016年 | 97篇 |
2015年 | 77篇 |
2014年 | 122篇 |
2013年 | 181篇 |
2012年 | 184篇 |
2011年 | 184篇 |
2010年 | 143篇 |
2009年 | 113篇 |
2008年 | 112篇 |
2007年 | 96篇 |
2006年 | 85篇 |
2005年 | 49篇 |
2004年 | 67篇 |
2003年 | 56篇 |
2002年 | 44篇 |
2001年 | 27篇 |
2000年 | 26篇 |
1999年 | 15篇 |
1998年 | 22篇 |
1997年 | 30篇 |
1996年 | 11篇 |
1995年 | 11篇 |
1994年 | 13篇 |
1993年 | 12篇 |
1992年 | 11篇 |
1990年 | 6篇 |
1989年 | 12篇 |
1988年 | 3篇 |
1987年 | 10篇 |
1986年 | 11篇 |
1985年 | 13篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有2487条查询结果,搜索用时 15 毫秒
41.
Bettina Fazzinga Sergio Flesca Andrea Tagarelli 《Knowledge and Information Systems》2011,26(1):127-173
An effective solution to automate information extraction from Web pages is represented by wrappers. A wrapper associates a Web page with an XML document that represents part of the information in that page in a machine-readable
format. Most existing wrapping approaches have traditionally focused on how to generate extraction rules, while they have
ignored potential benefits deriving from the use of the schema of the information being extracted in the wrapper evaluation. In this paper, we investigate how the schema of extracted information
can be effectively used in both the design and evaluation of a Web wrapper. We define a clean declarative semantics for schema-based wrappers by introducing the notion of (preferred) extraction model, which is essential to compute a valid XML document containing
the information extracted from a Web page. We developed the SCRAP (SChema-based wRAPper for web data) system for the proposed schema-based wrapping approach, which also provides visual support tools to the wrapper designer.
Moreover, we present a wrapper generalization framework to profitably speed up the design of schema-based wrappers. Experimental
evaluation has shown that SCRAP wrappers are not only able to successfully extract the required data, but also they are robust
to changes that may occur in the source Web pages. 相似文献
42.
A novel classifier is introduced to overcome the limitations of the k-NN classification systems. It estimates the posterior class probabilities using a local Parzen window estimation with the k-nearest-neighbour prototypes (in the Euclidean sense) to the pattern to classify. A learning algorithm is also presented to reduce the number of data points to store. Experimental results in two hand-written classification problems demonstrate the potential of the proposed classification system. 相似文献
43.
Entanglement of formation and concurrence for mixed states 总被引:1,自引:0,他引:1
Xiuhong Gao Albeverio Sergio Kai Chen Shaoming Fei Xianqing Li-Jost 《Frontiers of Computer Science in China》2008,2(2):114-128
We review some results on analytical computations of the measures for quantum entanglement: entanglement of formation and
concurrence. We introduce some estimations of the lower bounds for the entanglement of formation in bipartite mixed states,
and of lower bounds for the concurrence in bipartite and tripartite systems. The results on lower bounds for the concurrence
are also generalized to arbitrary multipartite systems. 相似文献
44.
Software Architectures for Reducing Priority Inversion and Non-determinism in Real-time Object Request Brokers 总被引:8,自引:0,他引:8
Schmidt Douglas C. Mungee Sumedh Flores-Gaitan Sergio Gokhale Aniruddha 《Real-Time Systems》2001,21(1-2):77-125
There is increasing demand to extend Object RequestBroker (ORB) middleware to support distributed applications withstringent real-time requirements. However, conventional ORB implementations,such as CORBA ORBs, exhibit substantial priority inversion andnon-determinism, which makes them unsuitable for applicationswith deterministic real-time requirements. This paper providestwo contributions to the study and design of real-time ORB middleware.First, it illustrates empirically why conventional ORBs do notyet support real-time quality of service. Second, it evaluatesconnection and concurrency software architectures to identifystrategies that reduce priority inversion and non-determinismin real-time CORBA ORBs. The results presented in this paperdemonstrate the feasibility of using standard OO middleware likeCORBA to support certain types of real-time applications overthe Internet. 相似文献
45.
Algorithmic and architectural design for real-time and power-efficient Retinex image/video processing 总被引:1,自引:1,他引:0
Sergio Saponara Luca Fanucci Stefano Marsi Giovanni Ramponi 《Journal of Real-Time Image Processing》2007,1(4):267-283
This paper presents novel algorithmic and architectural solutions for real-time and power-efficient enhancement of images
and video sequences. A programmable class of Retinex-like filters, based on the separation of the illumination and reflectance
components, is proposed. The dynamic range of the input image is controlled by applying a suitable non-linear function to
the illumination, while the details are enhanced by processing the reflectance. An innovative spatially recursive rational
filter is used to estimate the illumination. Moreover, to improve the visual quality results of two-branch Retinex operators
when applied to videos, a novel three-branch technique is proposed which exploits both spatial and temporal filtering. Real-time
implementation is obtained by designing an Application Specific Instruction-set Processor (ASIP). Optimizations are addressed
at algorithmic and architectural levels. The former involves arithmetic accuracy definition and linearization of non-linear
operators; the latter includes customized instruction set, dedicated memory structure, adapted pipeline, bypasses, custom
address generator, and special looping structures. The ASIP is synthesized in standard-cells CMOS technology and its performances
are compared to known Digital signal processor (DSP) implementations of real-time Retinex filters. As a result of the comparison,
the proposed algorithmic/architectural design outperforms state-of-art Retinex-like operators achieving the best trade-off
between power consumption, flexibility, and visual quality.
Sergio Saponara is a Research Scientist and Assistant Professor at the University of Pisa. He was born in Bari, Italy, in 1975. He received the Electronic Engineering degree cum laude and the Ph.D. in Information Engineering, both from Pisa University, in 1999 and 2003, respectively. Since 2001 he collaborates with Consorzio Pisa Ricerche, Italy and in 2002 he was with IMEC, Belgium as Marie Curie research fellow. His research and teaching interests include electronic circuits and systems for multimedia, telecom and automation. He co-authored more than 40 papers including journals, conferences and patents. Luca Fanucci is Associate Professor of Microelectronics at the University of Pisa. He was born in Montecatini, Italy, in 1965. He received the Doctor Engineer degree and the Ph.D. in Electronic Engineering from the University of Pisa in 1992 and 1996, respectively. From 1992 to 1996, he was with the European Space Agency's Research and Technology Center, Noordwijk, The Netherlands, and from 1996 to 2004 he was a Research Scientist of the Italian National Research Council in Pisa. His research interests include design technologies for integrated circuits and systems, with emphasis on system-level design, hardware/software co-design and low-power. He co-authored more than 100 journal/conference papers and holds more than 10 patents. Stefano Marsi was born in Trieste, Italy, in 1963. He received the Doctor Engineer degree in Electronic Engineering (summa cum laude) in 1990 and the Ph.D. degree in 1994. Since 1995 he has held the position of researcher in the Department of Electronics at the University of Trieste where he is the teacher of courses in electronic field. His research interests include non-linear operators for image and video processing and their realization through application specific electronics circuits. He is author or co-author of more than 40 papers in international journals, proceedings of international conferences or contributions in books. Giovanni Ramponi is Professor of Electronics at the Department of Electronics of the University of Trieste, Italy. His research interests include nonlinear digital signal processing, and the enhancement and feature extraction in images and image sequences. Prof. Ramponi has been an Associate Editor of the IEEE Signal Processing Letters and of the IEEE Transactions on Image Processing; presently is an AE of the SPIE Journal of Electronic Imaging. He has participated in various EU and National Research Projects. He is the co-inventor of various pending international patents and has published more than 140 papers in international journals and conference proceedings, and as book chapters. Prof. Ramponi contributes to several undergraduate and graduate courses on digital signal processing. 相似文献
Giovanni RamponiEmail: |
Sergio Saponara is a Research Scientist and Assistant Professor at the University of Pisa. He was born in Bari, Italy, in 1975. He received the Electronic Engineering degree cum laude and the Ph.D. in Information Engineering, both from Pisa University, in 1999 and 2003, respectively. Since 2001 he collaborates with Consorzio Pisa Ricerche, Italy and in 2002 he was with IMEC, Belgium as Marie Curie research fellow. His research and teaching interests include electronic circuits and systems for multimedia, telecom and automation. He co-authored more than 40 papers including journals, conferences and patents. Luca Fanucci is Associate Professor of Microelectronics at the University of Pisa. He was born in Montecatini, Italy, in 1965. He received the Doctor Engineer degree and the Ph.D. in Electronic Engineering from the University of Pisa in 1992 and 1996, respectively. From 1992 to 1996, he was with the European Space Agency's Research and Technology Center, Noordwijk, The Netherlands, and from 1996 to 2004 he was a Research Scientist of the Italian National Research Council in Pisa. His research interests include design technologies for integrated circuits and systems, with emphasis on system-level design, hardware/software co-design and low-power. He co-authored more than 100 journal/conference papers and holds more than 10 patents. Stefano Marsi was born in Trieste, Italy, in 1963. He received the Doctor Engineer degree in Electronic Engineering (summa cum laude) in 1990 and the Ph.D. degree in 1994. Since 1995 he has held the position of researcher in the Department of Electronics at the University of Trieste where he is the teacher of courses in electronic field. His research interests include non-linear operators for image and video processing and their realization through application specific electronics circuits. He is author or co-author of more than 40 papers in international journals, proceedings of international conferences or contributions in books. Giovanni Ramponi is Professor of Electronics at the Department of Electronics of the University of Trieste, Italy. His research interests include nonlinear digital signal processing, and the enhancement and feature extraction in images and image sequences. Prof. Ramponi has been an Associate Editor of the IEEE Signal Processing Letters and of the IEEE Transactions on Image Processing; presently is an AE of the SPIE Journal of Electronic Imaging. He has participated in various EU and National Research Projects. He is the co-inventor of various pending international patents and has published more than 140 papers in international journals and conference proceedings, and as book chapters. Prof. Ramponi contributes to several undergraduate and graduate courses on digital signal processing. 相似文献
46.
A novel technique for the quantification of the iron content of copper precipitates in ferritic steels is presented. Energy-filtered (EF) imaging has been used to extract elemental maps with high spatial resolution. These maps contain enough information to attempt the quantification of the signal produced by the precipitates when either a line profile is measured across them or the whole image signal is integrated. Assumptions such as sphericity of the precipitates and composition variations are discussed. Special attention to the assessment of drift on the information extracted from EF images has been taken. Minimum detectability and optimum acquisition conditions are discussed. 相似文献
47.
Sergio Orts Jose Garcia-Rodriguez Diego Viejo Miguel Cazorla Vicente Morell 《Journal of Parallel and Distributed Computing》2012
Self-organising neural models have the ability to provide a good representation of the input space. In particular the Growing Neural Gas (GNG) is a suitable model because of its flexibility, rapid adaptation and excellent quality of representation. However, this type of learning is time-consuming, especially for high-dimensional input data. Since real applications often work under time constraints, it is necessary to adapt the learning process in order to complete it in a predefined time. This paper proposes a Graphics Processing Unit (GPU) parallel implementation of the GNG with Compute Unified Device Architecture (CUDA). In contrast to existing algorithms, the proposed GPU implementation allows the acceleration of the learning process keeping a good quality of representation. Comparative experiments using iterative, parallel and hybrid implementations are carried out to demonstrate the effectiveness of CUDA implementation. The results show that GNG learning with the proposed implementation achieves a speed-up of 6× compared with the single-threaded CPU implementation. GPU implementation has also been applied to a real application with time constraints: acceleration of 3D scene reconstruction for egomotion, in order to validate the proposal. 相似文献
48.
Giulianella ColettiOsvaldo Gervasi Sergio TassoBarbara Vantaggi 《Computational statistics & data analysis》2012,56(4):967-980
A generalized Bayesian inference framework in order to embed fuzzy sets and partial probabilistic information is provided. The general framework of reference is that of coherent conditional probabilities, which allows giving a rigorous interpretation of membership function as a conditional probability, regarded as a function of the conditioning event. The inferential problem needs to be studied in situations where the prior can be partial; moreover, membership and prior can be given on different classes of events. This inferential model is applied for the virtual representation of a female avatar. 相似文献
49.
Salvi D Gorman J Arredondo MT Vera-Muñoz C Ottaviano M Salvi S 《Computer methods and programs in biomedicine》2012,107(1):45-52
Personalized health (p-health) systems can contribute significantly to the sustainability of healthcare systems, though their feasibility is yet to be proven. One of the problems related to their development is the lack of well-established development tools for this domain. As the p-health paradigm is focused on patient self-management, big challenges arise around the design and implementation of patient systems. This paper presents a reference platform created for the development of these applications, and shows the advantages of its adoption in a complex project dealing with cardio-vascular diseases. 相似文献
50.
Sergio L. González-Cortés Tian-Cun Xiao Nick Rees Dora Méhn Malcolm L.H. Green 《Materials Research Bulletin》2005,40(7):1112-1119
The first examples of mesostructured materials containing Mo- and W-oxo-sulphur species incorporated into a poorly ordered MCM-41 framework have been prepared under hydrothermal condition and alkaline medium. The incorporation of oxygen-sulphur derivates of molybdenum and tungsten not only increases significantly the pore diameter, but also improves the thermal stability of the MCM-41-related mesoporous material. 相似文献