全文获取类型
收费全文 | 214篇 |
免费 | 7篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 34篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
建筑科学 | 4篇 |
能源动力 | 9篇 |
轻工业 | 14篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 15篇 |
一般工业技术 | 43篇 |
冶金工业 | 49篇 |
原子能技术 | 7篇 |
自动化技术 | 32篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 9篇 |
2011年 | 13篇 |
2010年 | 6篇 |
2009年 | 7篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1985年 | 1篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1963年 | 2篇 |
1954年 | 1篇 |
1951年 | 1篇 |
1945年 | 1篇 |
排序方式: 共有221条查询结果,搜索用时 15 毫秒
71.
Memetic Pareto differential evolutionary neural network used to solve an unbalanced liver transplantation problem 总被引:1,自引:1,他引:0
M. Cruz-Ramírez C. Hervás-Martínez P. A. Gutiérrez M. Pérez-Ortiz J. Briceño M. de la Mata 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2013,17(2):275-284
Donor–recipient matching constitutes a complex scenario difficult to model. The risk of subjectivity and the likelihood of falling into error must not be underestimated. Computational tools for the decision-making process in liver transplantation can be useful, despite the inherent complexity involved. Therefore, a multi-objective evolutionary algorithm and various techniques to select individuals from the Pareto front are used in this paper to obtain artificial neural network models to aid decision making. Moreover, a combination of two pre-processing methods has been applied to the dataset to offset the existing imbalance. One of them is a resampling method and the other is a outlier deletion method. The best model obtained with these procedures (with AUC = 0.66) give medical experts a probability of graft survival at 3 months after the operation. This probability can help medical experts to achieve the best possible decision without forgetting the principles of fairness, efficiency and equity. 相似文献
72.
Susan A. Bernal John L. Provis David G. Brice Adam Kilcullen Peter Duxson Jannie S.J. van Deventer 《Cement and Concrete Research》2012,42(10):1317-1326
The carbonation resistance of alkali-activated binders is often tested via accelerated test protocols designed for Portland cements, without questioning whether the tests replicate the mechanisms observed in service. Thus, validation of accelerated methods is required to enable realistic prediction of material performance. Changes in pore solution equilibria cause the formation of sodium bicarbonates during accelerated carbonation, compared with hydrous sodium carbonates in natural carbonation. This shifts the carbonation mechanism to favour more rapid reaction progress, to give a higher apparent degree of acceleration (compared to natural conditions) than in Portland cements. The pore solution pH under accelerated carbonation is significantly lower than at natural CO2 concentrations, leading to a falsely short predicted service life (time to expected corrosion of embedded steel), as natural CO2 concentrations appear not to reduce the pH below 10. Thus, accelerated carbonation testing is unduly aggressive towards alkali-activated binders, and test results must be cautiously interpreted. 相似文献
73.
Luis Diego Briceño Howard Jay Siegel Anthony A. Maciejewski Mohana Oltikar 《The Journal of supercomputing》2012,62(1):461-485
Heterogeneous computing (HC) is the coordinated use of different types of machines, and networks to process a diverse workload in a manner that will maximize the combined performance and/or cost effectiveness of the system. Heuristics for allocating resources in an HC system are based on some optimization criterion. A common optimization criterion is to minimize the completion time of the machine that finishes last (makespan). In this study, we consider an iterative approach that repeatedly runs a mapping heuristic to minimize the makespan of the considered machines and tasks. For each successive iteration, the makespan machine of the previous iteration and the tasks assigned to it are removed from the set of considered machines and tasks. This study focuses on understanding the different mathematical characteristics of resource allocation heuristics that cause them to behave differently when combined with this iterative approach. This paper has three main contributions. The first contribution is the study of an iterative technique used in conjunction with resource allocation heuristics. The second contribution is the definition and mathematical characterization of “iteration invariant” heuristics. The third contribution is to determine the characteristics of a heuristic that will cause the mapping to change across iterations. 相似文献
74.
Camille Thevenot Didier Rouxel Sunija Sukumaran Sawsen Rouabah Brice Vincent Samir Chatbouri Tarak Ben Zineb 《应用聚合物科学杂志》2021,138(20):50420
In this work, flexible ferroelectric films of P(VDF-TrFE) softened by a plasticizer are elaborated. Morphology, piezoelectric, mechanical, thermal, and crystalline properties of the films are studied. We show that the elastic constant is reduced up to 30% while increasing the remanent polarization and the piezoelectric coefficient thanks to the lubricant property of the plasticizer, helping the orientation of the crystallites. Plus, the decrease of the coercive field from 46 to 32 V/μm after an annealing at 138°C for a plasticizer content ranging between 20 and 50 wt% is observed and an explanation by based on a polymer/plasticizer demixing is provided. It leads to an easier polarization process with a significant saving in time and applied electric field reducing the breakdown voltage. Both effects could be interesting for an industrial production. Finally, a first sensor is elaborated and characterized electrically with homemade test bench. We show that the softening of the P(VDF-TrFE) offers to the device a larger amplitude range of deformations. The combination of the flexibility with high ferroelectric properties of the plasticized P(VDF-TrFE) make it a very promising material for biomedical sensor applications. 相似文献
75.
O Dubourg A Dürr H Chneiweiss G Stevanin G Cancel C Penet Y Agid A Brice 《Canadian Metallurgical Quarterly》1995,151(11):657-660
Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder characterized by a degeneration of cerebellar and pallidal efferents, more frequent in Japan. Isolated cases are also encountered. Patients present with variable combination of signs including myoclonus, ataxia, epilepsy, choreoathetosis and dementia, with onset from childhood to the seventh decade. Clinically, DRPLA may be undistinguishable from other genetic disorders, in particular Huntington's disease or the spinocerebellar ataxias. The genetic basis of the inherited form of DRPLA is an expansion to more than 49 repeats of an unstable trinucleotide (CAG) in the DRPLA gene on the short arm of chromosome 12. We determined the frequency of this mutation in patients with the DRPLA phenotype. One hundred and seventeen patients with cerebellar ataxia, from 94 families and 23 isolated cases, as well as 3 patients from families with undiagnosed autosomal dominant neurodegenerative disorders were investigated for the presence of the expanded sequence. None of the patients carried this mutation. This finding suggests that DRPLA is rare in the French population. The search for the DRPLA mutation is justified in patients with the DRPLA phenotype, however, since genetic counselling is often requested and neither clinical, nor neuropathological examinations permit a definite diagnosis of the underlying disease. 相似文献
76.
77.
78.
The electrical conductivity of the oxides Li8CeO6 and Li8HfO6, which are thermodynamically stable against Li (1), has been studied under oxygen atmosphere in the temperature range between room temperature and 200°C. As for Li8ZrO6 and Li8SnO6 (2), the materials can be considered as solid electrolytes with medium conductivity. The interpretation of the results, considering the Ca2+ ions as impurities, are in agreement with those based on the diffusion mechanisms of the Li+ ions recently established by 7Li NMR in isostructural oxides by Simpson et al. (3). 相似文献
79.
80.
We report the first study of optical planar and channel waveguides fabricated in the new nonlinear crystal Ca4YO(BO3) by use of MeV He+-implantations. The nx, ny, and nz refractive index modifications are studied. Losses in nonannealed YCOB waveguides measured with a CCD camera are found to be less than 2 dB cm(-1). This work is the first step toward the investigation of frequency conversion within the obtained guiding structures. 相似文献