全文获取类型
收费全文 | 288篇 |
免费 | 13篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 49篇 |
金属工艺 | 2篇 |
机械仪表 | 2篇 |
建筑科学 | 10篇 |
能源动力 | 11篇 |
轻工业 | 33篇 |
水利工程 | 3篇 |
无线电 | 33篇 |
一般工业技术 | 23篇 |
冶金工业 | 4篇 |
原子能技术 | 2篇 |
自动化技术 | 128篇 |
出版年
2022年 | 10篇 |
2021年 | 12篇 |
2020年 | 11篇 |
2019年 | 9篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 10篇 |
2014年 | 9篇 |
2013年 | 17篇 |
2012年 | 18篇 |
2011年 | 16篇 |
2010年 | 23篇 |
2009年 | 26篇 |
2008年 | 15篇 |
2007年 | 16篇 |
2006年 | 10篇 |
2005年 | 10篇 |
2004年 | 13篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有301条查询结果,搜索用时 15 毫秒
71.
Georgios Kouroupis Vassilis Anastassopoulos 《International journal of remote sensing》2019,40(13):5121-5140
In this work, a novel ship detection procedure is presented for radar signals whose backscattering power is of the same order while their polarimetric characteristics differ greatly. The stochastic nature of the polarimetric characteristics of the background (clutter) and the target signal (ship) can be adequately described by first-order Markov chains (FMCs). The proposed feature corresponds to the joint probability of sequential states of variable finite sequential segments of the FMCs. The classic Constant False Alarm Rate (CFAR) detection theory is adapted to the discrete space of the Markov experimental distributions of the proposed feature while the adaptive thresholding technique is overcome by considering a global model for describing the clutter. Performance assessment of the proposed detection procedure is carried out by means of three sets of FMCs each one corresponding to a clutter-target pair for different lengths of the finite FMC segments. The experimental results present high detection scores making the proposed detection procedure ideal for signals characterized by the Markov property. A comparative study of previous detection approaches has been implemented that shows the superiority of the proposed detection procedure. 相似文献
72.
Vassilis S. Kouikoglou 《国际生产研究杂志》2013,51(17):4485-4503
This paper develops a discrete event simulation model of assembly/disassembly (AD) production networks with finite buffers and unreliable machines. The model is an extension of a previous continuous flow model, which simulates the system only when a machine's production rate is altered. The events causing changes in the production rates are: a machine fails or is repaired and a buffer becomes full, empty, not full, or not empty. During operation between two events the system runs deterministically. Thus, given the state of the system (machine cumulative production, buffer levels and their statistics) at the time of occurrence of some event, the corresponding state variables upon the occurrence of the next event can be updated using analysis. The proposed model does not use repair, not-full, and not-empty events. This is achieved by considering the machine downtimes as transient times in which no parts are produced and by developing more complex state equations. Numerical results show that the model combines speed and accuracy. 相似文献
73.
Hannu Kukka Vassilis Kostakos Timo Ojala Johanna Ylipulli Tiina Suopajärvi Marko Jurmu Simo Hosio 《Personal and Ubiquitous Computing》2013,17(1):15-27
We present a multipronged comparative study of citizens’ self-proclaimed information needs and actual information seeking behavior in smart urban spaces. We first conducted several user studies to identify the types of information services that citizens believed to be useful in urban setting utilizing methods ranging from contextual inquiry with lo-fi prototypes to “card sorting” exercise with a separate set of participants, and finally to implementing selected services. We then made a sizeable constructive intervention into the urban space by deploying in a city center 12 large, interactive public displays called “hotspots” to offer a wide range of previously identified information services. We collected comprehensive qualitative and quantitative data on the usage of the hotspots and their services by the general public during 13 months. Our study reveals discrepancies between a priori and a posteriori information seeking strategies extracted from the self-proclaimed information needs and the actual usage of the hotspots. 相似文献
74.
Abstract Mass transport properties of osmotic solutions are important in controlling osmotic dehydration process. In the first paper of the series “Mass Transfer Properties of Osmotic Solutions”;, data of water activities, osmotic pressure, osmosities or osmolalities and solute activities are presented. In the present paper, the literature data on diffusivities of both binary and multi‐component osmotic solutions are presented. Some aspects of measurement methodology and mass transfer modeling are also discussed. 相似文献
75.
Vassilis Kostoglou George Minos Emmanouil Tolis 《Information Systems and E-Business Management》2013,11(2):253-264
A dichotomous identification key organizes fishes based on their similarities and differences, and is an essential tool in which ichthyologists, biologists, fishery biologists and others can use for accurate identification of specimens or finding information on correct names, biology and distribution of species. This research work focuses on the development and implementation of a totally new information system that is able to identify correctly fish species names. The developed system is a fully interactive fish identification e-key, which can be used in both forms; locally and remotely via the World Wide Web. This new dichotomous classification e-key provides the capability to identify any species in a compact and easy to use environment, which gives the user excellent operation capabilities and complete information about all included fish species. Moreover, the application provides the capability to search for a random fish species and to show a list which includes all the fish species that currently exist in the application's database. There is an extra attribute that makes the new system novel, and this is its expandability: the information system is fully dynamic having the capability to be extended every time a new species is identified. This attribute is innovative because, until now, there is not any fish identification e-key that gives the user the capability to insert new fish species into the application's database. 相似文献
76.
77.
Kendrick RL Aubrun JN Bell R Benson R Benson L Brace D Breakwell J Burriesci L Byler E Camp J Cross G Cuneo P Dean P Digumerthi R Duncan A Farley J Green A Hamilton HH Herman B Lauraitis K de Leon E Lorell K Martin R Matosian K Muench T Ni M Palmer A Roseman D Russell S Schweiger P Sigler R Smith J Stone R Stubbs D Swietek G Thatcher J Tischhauser C Wong H Zarifis V Gleichman K Paxman R 《Applied optics》2006,45(18):4235-4240
A nine-aperture, wide-field Fizeau imaging telescope has been built at the Lockheed-Martin Advanced Technology Center. The telescope consists of nine, 125 mm diameter collector telescopes coherently phased and combined to form a diffraction-limited image with a resolution that is consistent with the 610 mm diameter of the telescope. The phased field of view of the array is 1 murad. The measured rms wavefront error is 0.08 waves rms at 635 nm. The telescope is actively controlled to correct for tilt and phasing errors. The control sensing technique is the method known as phase diversity, which extracts wavefront information from a pair of focused and defocused images. The optical design of the telescope and typical performance results are described. 相似文献
78.
Pampa Mukherjee Michael G.B. Drew Vassilis Tangoulis Marta Estrader Carmen Diaz Ashutosh Ghosh 《Inorganic chemistry communications》2009,12(9):929-932
A new linear trinuclear nickel(II) complex, [Ni3(salme)2(OCn)4] (Hsalme = 2-[(3-methylamino-propylimino)-methyl]-phenol, OCn = cinnamate), showing weak ferromagnetic coupling (J = 1.8(1) cm−1) through phenoxo and a novel tridentate bridging mode (1κ2OO′:2κO′) of the cinnamate ligand has been synthesized and structurally characterized by X-ray crystallography. 相似文献
79.
Adjusting transport segmentation policy of DTN Bundle Protocol under synergy with lower layers 总被引:2,自引:0,他引:2
Christos V. SamarasAuthor Vitae Vassilis Tsaoussidis Author Vitae 《Journal of Systems and Software》2011,84(2):226-237
We assess Delay-Tolerant Network (DTN) performance in space under the scope of adjusting protocol data unit (PDU) size at various layers. We quantify the importance of combinatively adjusting size of DTN bundles, transport packets, and link frames. Through simulations, our paper reveals trade-offs that involve file delivery time, transmission effort of sending nodes, and memory resources release rate. Based on our findings, we propose a transport adaptation scheme that dynamically adjusts DTN bundle and transport packet size by means of heuristic search. To our knowledge, this is the first study to examine transport segmentation policy and interaction among various layers of the DTN protocol stack. 相似文献
80.
With the proliferation of the Web and ICT technologies there have been concerns about the handling and use of sensitive information by data mining systems. Recent research has focused on distributed environments where the participants in the system may also be mutually mistrustful. In this paper we discuss the design and security requirements for large-scale privacy-preserving data mining (PPDM) systems in a fully distributed setting, where each client possesses its own records of private data. To this end we argue in favor of using some well-known cryptographic primitives, borrowed from the literature on Internet elections. More specifically, our framework is based on the classical homomorphic election model, and particularly on an extension for supporting multi-candidate elections. We also review a recent scheme [Z. Yang, S. Zhong, R.N. Wright, Privacy-preserving classification of customer data without loss of accuracy, in: SDM’ 2005 SIAM International Conference on Data Mining, 2005] which was the first scheme that used the homomorphic encryption primitive for PPDM in the fully distributed setting. Finally, we show how our approach can be used as a building block to obtain Random Forests classification with enhanced prediction performance. 相似文献