全文获取类型
收费全文 | 2173篇 |
免费 | 140篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 31篇 |
综合类 | 2篇 |
化学工业 | 577篇 |
金属工艺 | 25篇 |
机械仪表 | 102篇 |
建筑科学 | 85篇 |
矿业工程 | 1篇 |
能源动力 | 76篇 |
轻工业 | 251篇 |
水利工程 | 21篇 |
石油天然气 | 4篇 |
无线电 | 197篇 |
一般工业技术 | 346篇 |
冶金工业 | 233篇 |
原子能技术 | 5篇 |
自动化技术 | 362篇 |
出版年
2024年 | 6篇 |
2023年 | 29篇 |
2022年 | 118篇 |
2021年 | 131篇 |
2020年 | 66篇 |
2019年 | 87篇 |
2018年 | 92篇 |
2017年 | 68篇 |
2016年 | 100篇 |
2015年 | 71篇 |
2014年 | 103篇 |
2013年 | 146篇 |
2012年 | 121篇 |
2011年 | 138篇 |
2010年 | 127篇 |
2009年 | 121篇 |
2008年 | 114篇 |
2007年 | 83篇 |
2006年 | 67篇 |
2005年 | 66篇 |
2004年 | 46篇 |
2003年 | 60篇 |
2002年 | 55篇 |
2001年 | 31篇 |
2000年 | 19篇 |
1999年 | 32篇 |
1998年 | 33篇 |
1997年 | 23篇 |
1996年 | 19篇 |
1995年 | 20篇 |
1994年 | 21篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1964年 | 2篇 |
排序方式: 共有2318条查询结果,搜索用时 46 毫秒
61.
SAR interferometry based on Permanent Scatterers (PS-InSAR™) is used here to study the present crustal mobility of a large area of NW Italy, in the Piemonte region.Thirty-eight satellite scenes (ERS SAR), taken from May 1992 to January 2001, were analysed for detecting more than 2 million PS on the study area. Continuous velocity surface maps (Iso-Kinematic Maps: IKM) were obtained from geo-statistical and spatial cluster techniques (Hot Spot analysis) of PS “short-period” data, to identify relative ground motions and to compare them with “long-period” tectonic mobility trends, i.e. those inferred at regional scale over geological times (some million years).The comparison was made by individuation of homogeneous kinematic areas, represented in the IKM, and characterization of the boundaries between them (Iso-Kinematic Boundaries: IKB). The IKB were used as tools to asses if the PS-InSAR data on present-day crustal mobility could fit with the distribution of real tectonic structures or field geological elements.IKM were drawn for uplifting geological sectors of Piemonte (Maritime Alps, Gran Paradiso, Langhe) where moderate to very low seismicity is recorded, and gravitational instabilities of rock mass on mountain slopes are widespread. The land sectors have been chosen in order to test the suitability of IKM in very different geo-morphological conditions.Different types of correspondence between the IKM and the geological kinematic trend were found:
- -
- a first type in which the kinematic trend of short-period (a decade of years, i.e. the PS-InSAR detection time span) is in agreement with a long-period tectonic trend (some million years) and seem to be driven by well known faults subparallel to the IKB. These kinematic trends can be hidden by the slope movement due to gravitational instabilities;
- -
- a second type in which the kinematic trend of short-period does not strictly correspond to the long-period trend, but can be considered as minor-order, uplifting-subsidence cycles, even if in contrast with the long-period kinematic trend. Alternatively, the short-period kinematic trends could reflect the action of deep-seated geological forces or structures, not yet known or inferable (at least with the recorded PS-InSAR velocities) on the basis of the available geological data and models.
62.
Motivated by the increasing interest of the Computer Science community in the study and understanding of non-cooperative systems, we present a novel model for formalizing the rational behavior of agents with a more farsighted view of the consequences of their actions. This approach yields a framework creating new equilibria, which we call Second Order equilibria, starting from a ground set of traditional ones. By applying our approach to pure Nash equilibria, we define the set of Second Order pure Nash equilibria and present their applications to the Prisoner’s Dilemma game, to an instance of Braess’s Paradox in the Wardrop model and to the KP model with identical machines. 相似文献
63.
The problem of efficiently finding similar items in a large corpus of high-dimensional data points arises in many real-world
tasks, such as music, image, and video retrieval. Beyond the scaling difficulties that arise with lookups in large data sets,
the complexity in these domains is exacerbated by an imprecise definition of similarity. In this paper, we describe a method
to learn a similarity function from only weakly labeled positive examples. Once learned, this similarity function is used
as the basis of a hash function to severely constrain the number of points considered for each lookup. Tested on a large real-world
audio dataset, only a tiny fraction of the points (~0.27%) are ever considered for each lookup. To increase efficiency, no
comparisons in the original high-dimensional space of points are required. The performance far surpasses, in terms of both
efficiency and accuracy, a state-of-the-art Locality-Sensitive-Hashing-based (LSH) technique for the same problem and data
set. 相似文献
64.
Sergio Saponara Michele Casula Luca Fanucci 《Journal of Real-Time Image Processing》2008,3(3):201-216
To meet both flexibility and performance requirements, particularly when implementing high-end real-time image/video processing
algorithms, the paper proposes to combine the application specific instruction-set processor (ASIP) paradigm with the reconfigurable
hardware one. As case studies, the design of partially reconfigurable ASIP (r-ASIP) architectures is presented for two classes
of algorithms with widespread diffusion in image/video processing: motion estimation and retinex filtering. Design optimizations
are addressed at both algorithmic and architectural levels. Special processor concepts used to trade-off performance versus
flexibility and to enable new features of post-fabrication configurability are shown. Silicon implementation results are compared
to known ASIC, DSP or reconfigurable designs; the proposed r-ASIPs stand for their better performance–flexibility figures
in the respective algorithmic class.
Sergio Saponara got the Laurea degree, cum laude, and the Ph.D. in Electronic Engineering from the University of Pisa in 1999 and 2003, respectively. In 2002, he was with IMEC, Leuven (B), as Marie Curie Research Fellow. Since 2001, he collaborates with Consorzio Pisa Ricerche-TEAM in Pisa. He is senior researcher at the University of Pisa in the field of VLSI circuits and systems for telecom, multimedia, space and automotive applications. He is co-author of more than 80 scientific publications. He holds the chair of electronic systems for automotive and automation at the Faculty of Engineering. Michele Casula received the Laurea degree in Electronic Engineering from the University of Pisa in 2005. Since 2006, he is pursuing a Ph.D. degree in Information Engineering at the same university. His current interests involve VLSI circuits design, computer graphics, and Network-on-Chips. Luca Fanucci received the Laurea degree and the Ph.D. degree in Electronic Engineering from the University of Pisa in 1992 and 1996, respectively. From 1992 to 1996, he was with ESA/ESTEC, Noordwijk (NL), as a research fellow. From 1996 to 2004, he was a senior researcher of the Italian National Research Council in Pisa. He is Professor of Microelectronics at the University of Pisa. His research interests include design methodologies and hardware/software architectures for integrated circuits and systems. Prof. Fanucci has co-authored more than 100 scientific publications and he holds more than ten patents. 相似文献
Luca FanucciEmail: |
Sergio Saponara got the Laurea degree, cum laude, and the Ph.D. in Electronic Engineering from the University of Pisa in 1999 and 2003, respectively. In 2002, he was with IMEC, Leuven (B), as Marie Curie Research Fellow. Since 2001, he collaborates with Consorzio Pisa Ricerche-TEAM in Pisa. He is senior researcher at the University of Pisa in the field of VLSI circuits and systems for telecom, multimedia, space and automotive applications. He is co-author of more than 80 scientific publications. He holds the chair of electronic systems for automotive and automation at the Faculty of Engineering. Michele Casula received the Laurea degree in Electronic Engineering from the University of Pisa in 2005. Since 2006, he is pursuing a Ph.D. degree in Information Engineering at the same university. His current interests involve VLSI circuits design, computer graphics, and Network-on-Chips. Luca Fanucci received the Laurea degree and the Ph.D. degree in Electronic Engineering from the University of Pisa in 1992 and 1996, respectively. From 1992 to 1996, he was with ESA/ESTEC, Noordwijk (NL), as a research fellow. From 1996 to 2004, he was a senior researcher of the Italian National Research Council in Pisa. He is Professor of Microelectronics at the University of Pisa. His research interests include design methodologies and hardware/software architectures for integrated circuits and systems. Prof. Fanucci has co-authored more than 100 scientific publications and he holds more than ten patents. 相似文献
65.
Aliaksei Kerhet Michele Magno Francesco Leonardi Andrea Boni Luca Benini 《Journal of Real-Time Image Processing》2007,2(4):331-342
In this paper we propose MicrelEye, a wireless video node for cooperative distributed video processing applications that involve
image classification. The node is equipped with a low-cost VGA CMOS image sensor, a reconfigurable processing engine (FPGA,
Microcontroller, SRAM) and a Bluetooth 100-m transceiver. It has a size of few cubic centimeters and its typical power consumption
is approximately ten times less than that of typical commercial DSP-based solutions. As regards classification, a highly optimized
hardware-oriented support vector machine-like (SVM-like) algorithm called ERSVM is proposed and implemented. We describe our
hardware and software architecture, its performance and power characteristics. The case study considered in this paper is
people detection. The obtained results suggest that the present technology allows for the design of simple intelligent video
nodes capable of performing classification tasks locally.
相似文献
Luca BeniniEmail: |
66.
67.
Under natural viewing conditions, the physiological instability of visual fixation keeps the projection of the stimulus on the retina in constant motion. After eye opening, chronic exposure to a constantly moving retinal image might influence the experience-dependent refinement of cell response characteristics. The results of previous modeling studies have suggested a contribution of fixational instability to the Hebbian maturation of the receptive fields of V1 simple cells (Rucci, Edelman, & Wray, 2000; Rucci & Casile, 2004). This letter examines the origins of such a contribution. Using quasilinear models of lateral geniculate nucleus units and V1 simple cells, we derive analytical expressions for the second-order statistics of thalamocortical activity before and after eye opening. We show that in the presence of natural stimulation, fixational instability introduces a spatially uncorrelated signal in the retinal input, which strongly influences the structure of correlated activity in the model. This input signal produces a regime of thalamocortical activity similar to that present before eye opening and compatible with the Hebbian maturation of cortical receptive fields. 相似文献
68.
BPMN: An introduction to the standard 总被引:1,自引:0,他引:1
Michele ChinosiAuthor Vitae Alberto TrombettaAuthor Vitae 《Computer Standards & Interfaces》2012,34(1):124-134
The Business Process Model and Notation (BPMN) is the de-facto standard for representing in a very expressive graphical way the processes occurring in virtually every kind of organization one can think of, from cuisine recipes to the Nobel Prize assignment process, incident management, e-mail voting systems, travel booking procedures, to name a few. In this work, we give an overview of BPMN and we present what are the links with other well-known machineries such as BPEL and XPDL. We give an assessment of how the OMG's BPMN standard is perceived and used by practitioners in everyday business process modeling chores. 相似文献
69.
Programmers productivity has always been overlooked as compared to the performance optimizations in high performance computing
(HPC) community. In many parallel programming languages like MPI/MPI-IO, the performance optimizations are provided as various
function options to the programmers. In order to write an efficient code, they are required to know the exact usage of the
optimization functions, hence programmer productivity is limited. In this paper, we present RFSA, a Reduced Function Set Abstraction
based on an existing parallel programming interface (MPI-IO) for I/O. The purpose of RFSA is to hide the performance optimization
functions from the application developer, and relieve the application developer from deciding on a specific function. The
proposed set of functions rely on a selection algorithm to decide among the most common optimizations provided by MPI-IO.
We implement a selection algorithm for I/O functions like read, write, etc., and also merge a set of functions for data types
and file views. By running different parallel I/O benchmarks on both medium-scale clusters and NERSC supercomputers, we show
an improved programmer productivity (35.7% on average). This approach incurs an overhead of 2–5% for one particular optimization,
and shows performance improvement of 17% when a combination of different optimizations is required by an application. 相似文献
70.
Michele?RisiEmail author Giuseppe?Scanniello Genoveffa?Tortora 《Formal Aspects of Computing》2012,24(3):307-330
In this paper we present an approach to automate the architecture recovery process of software systems. The approach is built
on information retrieval and clustering techniques, and, in particular, uses Latent Semantic Indexing (LSI) to get similarities
among software entities (e.g., programs or classes) and the k-means clustering algorithm to form groups of software entities
that implement similar functionality. In order to improve computational time in the context of the software evolution and
then reduce energy waste, the architecture recovery process can be also applied by using fold-in and fold-out mechanisms that,
respectively, add and remove software entities to the LSI representation of the understudy software system. The approach has
been implemented in a prototype of a supporting software system as an Eclipse plug-in. Finally, to assess the approach and
the plug-in, we have conducted an empirical investigation on five open source software systems implemented using the programming
languages Java and C/C++. In the investigation special emphasis has been also given to the effect of using the fold-in and
fold-out mechanisms. 相似文献