全文获取类型
收费全文 | 184篇 |
免费 | 4篇 |
专业分类
化学工业 | 33篇 |
机械仪表 | 1篇 |
建筑科学 | 15篇 |
能源动力 | 7篇 |
轻工业 | 9篇 |
石油天然气 | 2篇 |
无线电 | 34篇 |
一般工业技术 | 24篇 |
冶金工业 | 25篇 |
原子能技术 | 1篇 |
自动化技术 | 37篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 8篇 |
2011年 | 8篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 6篇 |
2007年 | 7篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 9篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 5篇 |
1971年 | 1篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有188条查询结果,搜索用时 15 毫秒
61.
A Statistical Theory for Quantitative Association Rules 总被引:7,自引:0,他引:7
Association rules are a key data-mining tool and as such have been well researched. So far, this research has focused predominantly on databases containing categorical data only. However, many real-world databases contain quantitative attributes and current solutions for this case are so far inadequate. In this paper we introduce a new definition of quantitative association rules based on statistical inference theory. Our definition reflects the intuition that the goal of association rules is to find extraordinary and therefore interesting phenomena in databases. We also introduce the concept of sub-rules which can be applied to any type of association rule. Rigorous experimental evaluation on real-world datasets is presented, demonstrating the usefulness and characteristics of rules mined according to our definition. 相似文献
62.
P. Jonathon Phillips Yehuda Vardi Stanley M. Dunn Monte S. Buchsbaum Jacqueline L. Spiegel-Cohen 《International journal of imaging systems and technology》1998,9(1):46-50
We present an algorithm to automatically register magnetic resonance (MR) and positron emission tomographic (PET) images of the human brain. Our algorithm takes an integrated approach: we simultaneously segment the brain in both modalities and register the slices. The algorithm does not attempt to remove the skull from the MR image, but rather uses “templates” constructed from PET images to locate the boundary between the brain and the surrounding tissue in the MR images. The PET templates are a sequence of estimates of the boundary of the brain in the PET images. For each of the templates, the registration algorithm aligns the MR and PET images by minimizing an energy function. The energy function is designed to implicitly model the relevant anatomical structure in the MR image. The template with the lowest energy after registration is the PET brain boundary. The alignment of this template in the MR image marks the MR brain boundary and gives the transformation between the two images. © 1998 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 9, 46–50, 1998 相似文献
63.
Yehuda Lindell 《Journal of Cryptology》2006,19(3):359-377
In this paper we present a simpler construction of a public-key
encryption scheme that achieves adaptive chosen ciphertext
security (CCA2), assuming the existence of trapdoor permutations.
We build on previous works of Sahai and De Santis et al. and
construct a scheme that we believe is the easiest to understand to
date. In particular, it is only slightly more involved than the
Naor--Yung encryption scheme that is secure against passive
chosen-ciphertext attacks (CCA1). We stress that the focus of this
paper is on simplicity only. 相似文献
64.
Methods used to experimentally estimate the binding energies of van der Waals clusters containing an aromatic molecule are surveyed. These include microwave and infrared absorption spectroscopies, single and two photon ionization, dispersed fluorescence, and stimulated emission pumping. The problems encountered in the application of these methods are briefly discussed, and prospects for the firm establishment of the binding energies are assessed. Although the present database is too small for firm conclusions, methods based on dispersed fluorescence (i.e., probing the excited state surface) tend to yield lower values for argon adducts than those based on ionization, probing the ground state, or ionic surfaces. A mechanism that may account for this tendency is proposed, and further experiments are proposed to test it. 相似文献
65.
Improved BGP convergence via ghost flushing 总被引:6,自引:0,他引:6
Afek Y. Bremler-Barr A. Schwarz S. 《Selected Areas in Communications, IEEE Journal on》2004,22(10):1933-1948
Labovitz et al. (2001) and Labovitz et al. (2000) noticed that sometimes it takes border gateway protocol (BGP) a substantial amount of time and messages to converge and stabilize following the failure of some node in the Internet. In this paper, we suggest a minor modification to BGP that eliminates the problem pointed out and substantially reduces the convergence time and communication complexity of BGP. Roughly speaking, our modification ensures that bad news (the failure of a node/edge) propagate fast, while good news (the establishment of a new path to a destination) propagate somewhat slower. This is achieved in BGP by allowing withdrawal messages to propagate with no delay as fast as the network forward them, while announcements propagate as they do in BGP with a delay at each node of one minRouteAdver (except for the first wave of announcements). As a by product of this work, a new stateless mechanism to overcome the counting to infinity problem is provided, which compares favorably with other known stateless mechanisms (in RIP and IGRP). 相似文献
66.
Ludwig A Leviatan Y 《Journal of the Optical Society of America. A, Optics, image science, and vision》2003,20(8):1553-1562
We introduce a solution based on the source-model technique for periodic structures for the problem of electromagnetic scattering by a two-dimensional photonic bandgap crystal slab illuminated by a transverse-magnetic plane wave. The proposed technique takes advantage of the periodicity of the slab by solving the problem within the unit cell of the periodic structure. The results imply the existence of a frequency bandgap and provide a valuable insight into the relationship between the dimensions of a finite periodic structure and its frequency bandgap characteristics. A comparison shows a discrepancy between the frequency bandgap obtained for a very thick slab and the bandgap obtained by solving the corresponding two-dimensionally infinite periodic structure. The final part of the paper is devoted to explaining in detail this apparent discrepancy. 相似文献
67.
Topological fisheye views for visualizing large graphs 总被引:1,自引:0,他引:1
Gansner ER Koren Y North SC 《IEEE transactions on visualization and computer graphics》2005,11(4):457-468
Graph drawing is a basic visualization tool that works well for graphs having up to hundreds of nodes and edges. At greater scale, data density and occlusion problems often negate its effectiveness. Conventional pan-and-zoom, multiscale, and geometric fisheye views are not fully satisfactory solutions to this problem. As an alternative, we propose a topological zooming method. It precomputes a hierarchy of coarsened graphs that are combined on-the-fly into renderings, with the level of detail dependent on distance from one or more foci. A related geometric distortion method yields constant information density displays from these renderings. 相似文献
68.
Feeding of theophylline to hornet workers from their moment of eclosion during the summer results in the following effects on the hornets: loss of appetite for proteins, inhibited ovarial development, no cell-building activity, negative phototaxis, gradual slow-down of spontaneous motor activity, difficulty in flight and orientation, and an overall behavior pattern reminiscent of hornet queens in nature when they are in a state of winter diapause. These findings suggest that theophylline exerts anti-juvenile-hormone-like effects on hornets and raise the possibility of utilizing theophylline baits to suppress pest hornet populations. 相似文献
69.
Ben-Yishay Yehuda; Diller Leonard; Mandleberg Ian; Gordon Wayne; Gerstman Louis J. 《Canadian Metallurgical Quarterly》1971,78(1):17
Developed an objective scoring system to determine whether right and left hemiplegics differ from normal controls, and from one another, in terms of competence levels, style of performance, constructional deviations, and various rates of activity while attempting to solve block designs. A microanalysis of the wais block design performances of 40 normals, 56 right hemiplegics, and 49 left hemiplegics was conducted. Results indicate that (a) brain-injured ss were inferior to normals in competence, (b) brain-injured ss did not differ from normals in style of performance and in partial competence, (c) right hemiplegic ss differed from left hemiplegic ss on all parameters of performance but competence level. Theoretical and clinical implications are discussed. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.
Yehuda E. Kalay 《Computer aided design》1983,15(3):141-146
Since the beginning of geometric modelling as a field of CAD a decade ago, the methods for interactive design of solid objects and interactive design of free-formed surfaces (of degree three and higher) were developed along parallel yet disjoint lines. One led to the development of techniques for representing and manipulating the shape of polyhedral solids bounded mostly by planes, while the other led to the development of techniques for the mathematical representation of curved surfaces, without paying attention to their combination into volumetric solids. Though the need for integrating solid object modelling with surface modelling for the design of such artefacts as machine parts, aircraft, cars and ships has been widely recognized, there is so far no single modelling system which provides such capabilities in a general way.An integrated solids modelling system for representing and manipulating polyhedral objects bounded by bicubic parametric surfaces is presented. Its basic capabilities include the representation of solids through a surface-based model, such that the surface underlying any face can be replaced by another surface that has been modelled independently. Other functionalities include scaling, rotation and translation of shapes and their pairwise combination into more complex shapes by means of spatial set operators. 相似文献