全文获取类型
收费全文 | 79篇 |
免费 | 1篇 |
专业分类
化学 | 27篇 |
数学 | 34篇 |
物理学 | 8篇 |
无线电 | 11篇 |
出版年
2022年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 5篇 |
2011年 | 3篇 |
2010年 | 7篇 |
2009年 | 5篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1985年 | 1篇 |
排序方式: 共有80条查询结果,搜索用时 15 毫秒
1.
2.
COSEARCH: A Parallel Cooperative Metaheuristic 总被引:1,自引:0,他引:1
In order to design a well-balanced metaheuristic for robustness, we propose the COSEARCH approach which manages the cooperation
of complementary heuristic methods via an adaptive memory which contains a history of the search already done. In this paper,
we present the idiosyncrasies of the COSEARCH approach and its application for solving large scale instances of the quadratic
assignment problem (QAP). We propose an original design of the adaptive memory in order to focus on high quality regions of
the search and avoid attractive but deceptive areas. For the QAP, we have hybridized three heuristic agents of complementary
behaviours: a Tabu Search is used as the main search algorithm, a Genetic Algorithm is in charge of the diversification and
a Kick Operator is applied to intensify the search. The evaluations have been executed on large scale network of workstations
via a parallel environment which supports fault tolerance and adaptive dynamic scheduling of tasks. 相似文献
3.
Talbi H Billaud D Louarn G Pron A 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,56(4):717-728
Spectroelectrochemical properties of conducting poly(5-cyanoindole) films deposited on indium tin oxide (ITO) and platinum electrodes are investigated using UV-vis and resonant Raman spectroscopies. The transitions from undoped to semi-conducting state of P5CN require the partial oxidation of the polymer to create radical-cations by insertion of charge-neutralizing anions into the polymer. In order to obtain detailed structural information from the vibrational spectra, it is necessary to know the vibrational modes of oxidation-sensitive bands. Vibrational assignments were made on the basis of the results obtained on polyindole and P5CN in acetonitrile solution. The drastic changes in optical absorption and Raman spectra observed at various stage of oxidation were explained by the conversions between at least three different structures. On the basis of the Raman spectra, we have identified the vibrational modes associated with neutral and polaronic segments. The perturbation associated with the coexistence of these polaronic segments has been described as a quinoid structure growing on the expense of the benzoid one. The results obtained indicate that the molecular properties of the conducting polymers at various stages of an oxidation are better revealed by in-situ Raman spectra than by ex-situ studies. 相似文献
4.
5.
6.
7.
Higher homotopy of graphs has been defined in several articles. In Dochterman (Hom complexes and homotopy theory in the category of graphs. arXiv math/0605275 v2,28/09/2006, 2006), the authors asked for a companion homology theory. We define such a theory for the category of unoriented reflexive graphs; it exhibits a long exact sequence for a pair of graphs (G, A), satisfies an excision property and a Hurewicz theorem. This allows us to compute the top homology of the graphical n-spheres showing that the theory is not trivial and is able to detect n-dimensional holes in a graph. The long-term objective is to compare the homotopy of the topological and graphical spheres. 相似文献
8.
Plouchart J.-O. Jonghae Kim Zamdmer N. Liang-Hung Lu Sherony M. Tan Y. Groves R.A. Trzcinski R. Talbi M. Ray A. Wagner L.F. 《Solid-State Circuits, IEEE Journal of》2004,39(9):1455-1461
This paper presents five-stage and seven-stage traveling-wave amplifiers (TWA) in a 0.12-/spl mu/m SOI CMOS technology. The five-stage TWA has a 4-91-GHz bandpass frequency with a gain of 5 dB. The seven-stage TWA has a 5-86-GHz bandpass frequency with a gain of 9 dB. The seven-stage TWA has a measured 18-GHz noise figure, output 1-dB compression point, and output third-order intercept point of 5.5 dB, 10 dBm, and 15.5 dBm, respectively. The power consumption is 90 and 130 mW for the five-stage and seven-stage TWA, respectively, at a voltage power supply of 2.6 V. The chips occupy an area of less than 0.82 and 1 mm for the five-stage and seven-stage TWA, respectively. 相似文献
9.
This paper reports line-of-sight propagation measurements performed at 37.2GHz between two terminals in an empty room in order to investigate the spatialand temporal fadings in terms of antenna directivity and human motion,respectively. The empirical data base consists of recordings of CW envelopefading waveforms with a fixed transmitter and either moving or stationaryreceiver. The reported results include amplitude fading distributions,propagation loss gradients, level crossing rates and fade durationsstatistics. These results can be used in the modeling, design reliableoperation of local multi-point communication systems. 相似文献
10.
Unless procedures for the economic evaluation of flexible manufacturing technology are revamped, much of U.S. industry could repeat the experience of American automobile and steel companies from the recent past. The dynamic character of flexible manufacturing technology in terms of associated developments in microelectronics, a trend toward equipment modularity, and the increasing diversity of relevant markets make flexible manufacturing especially vulnerable to the weaknesses of conventional procedures for the justification of capital expenditures. Building on the work of V. Smith, M.I. Kamien and N.L. Schwartz, this paper presents optimization models from which economically reasonable plans can be derived for the implementation of flexible manufacturing technology. Although the assumptions of these models are not focused on the situation of a specific plant, model implications and the overall perspectives here on the economic evaluation of flexible system options should provide general guidance for manufacturing planners. 相似文献