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Julien Mouli-Castillo Stuart R. Haszeldine Kevin Kinsella Mark Wheeldon Angus McIntosh 《International Journal of Hydrogen Energy》2021,46(29):16217-16231
The increased reliance on natural gas for heating worldwide makes the search for carbon-free alternatives imperative, especially if international decarbonisation targets are to be met. Hydrogen does not release carbon dioxide (CO2) at the point of use which makes it an appealing candidate to decarbonise domestic heating. Hydrogen can be produced from either 1) the electrolysis of water with no associated carbon emissions, or 2) from methane reformation (using steam) which produces CO2, but which is easily captured and storable during production. Hydrogen could be transported to the end-user via gas distribution networks similar to, and adapted from, those in use today. This would reduce both installation costs and end-user disruption. However, before hydrogen can provide domestic heat, it is necessary to assess the ‘risk’ associated with its distribution in direct comparison to natural gas. Here we develop a comprehensive and multi-faceted quantitative risk assessment tool to assess the difference in ‘risk’ between current natural gas distribution networks, and the potential conversion to a hydrogen based system. The approach uses novel experimental and modelling work, scientific literature, and findings from historic large scale testing programmes. As a case study, the risk assessment tool is applied to the newly proposed H100 demonstration (100% hydrogen network) project. The assessment includes the comparative risk of gas releases both upstream and downstream of the domestic gas meter. This research finds that the risk associated with the proposed H100 network (based on its current design) is lower than that of the existing natural gas network by a factor 0.88. 相似文献
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We examine the compression and stability of spheromaks for magnetic field generation and heating by use of the 3D extended
MHD code, NIMROD [C.R. Sovinec, et al., J. Comp. Phys. 195, 355 (2004)]. The formation of compact tori (CT) plasmas with strong magnetic fields by use of repetitive CT injection is
being investigated experimentally and serves as impetus for this computational study. To reach high fields, the injected CT
will require compression before injection. Stability of the spheromak to tilt and shift modes is examined during compression,
as is the amplification of flux during co-helicity spheromak merging. 相似文献
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The history of computer modelling of the Wairakei geothermal field is reviewed. It covers the development of lumped-parameter models during the 1970s and then discusses the evolution and first applications of geothermal reservoir simulation techniques. The development of reservoir models of Wairakei at the University of Auckland began in the early 1980s; current models produces good matches against field data. Many future scenarios have been run using the University's models and have been presented at various regulatory hearings. The general conclusion from these scenarios is that Wairakei can continue producing electricity at the current level for at least another 50 years, and if Wairakei is shut down after 100 years of operation it will recover to its pre-exploitation state after a further 300 years. 相似文献
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In this study it is demonstrated that, with respect to model formulation, the number of linear and nonlinear equations involved in water distribution networks can be reduced to the number of closed simple loops. Regarding the optimization technique, a discrete state transition algorithm (STA) is introduced to solve several cases of water distribution networks. Firstly, the focus is on a parametric study of the ‘restoration probability and risk probability’ in the dynamic STA. To deal effectively with head pressure constraints, the influence is then investigated of the penalty coefficient and search enforcement on the performance of the algorithm. Based on the experience gained from training the Two-Loop network problem, a discrete STA has successfully achieved the best known solutions for the Hanoi, triple Hanoi and New York network problems. 相似文献
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最新研究表明贴身穿细美利奴羊毛的衣服对敏感型皮肤的皮疹有一定的治疗作用。为了确保这类过敏性皮肤穿着的舒适性,文章利用澳大利亚羊业合作研究中心的穿着试验数据和成衣,借助新近研发的羊毛舒适仪,对过敏性皮肤贴身穿轻薄毛织物的医用规格进行了研究。通过相关性分析发现:纯羊毛织物的刺痒性能很大程度上决定了穿着者的皮肤舒适度。进而通过使用多元变量主成分分析,辨别出人们对羊毛织物刺痒性能在不同的穿着环境和不同的活动强度下的感应模式,从而对织物的刺痒性能进行分类。最后通过对试穿服装的纤维细度和舒适度指数进行测试分析,确定了该类贴身穿毛织物的主要医用规格。包括舒适度指数不高于200,纤维的平均直径不大于17.5μm,直径大于25μm的纤维含量不高于2.0%。 相似文献
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The structural chemistry of nanoscale materials encapsulated within single-walled carbon nanotubes (SWNTs) is reviewed. SWNTs form atomically thin channels within a restricted diameter range, and their internal van der Waals surfaces regulate the growth behavior of encapsulated crystals in a precise fashion, leading to atomically regulated growth. The structural properties of these systems are largely dictated by the structural chemistry of the bulk material, although significant deviations from bulk structures are often observed, with lower surface coordinations and substantial lattice distortions. 相似文献
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Around 40% of 10-11-year-old children receive cycle training every year in the UK, but concern has been expressed over the efficacy of training courses. One argument is that accidents occur too infrequently to be a viable evaluative criterion, and attitudes and behaviour have been suggested as alternatives. A questionnaire that measured a number of variables including accidents, attitudes, and behaviour was completed by 336 participants from two schools in the London Borough of Bromley. At least one cycling injury had been sustained by 58.3% of respondents, requiring hospital treatment in 19.1% of cases. Girls reported fewer accidents than boys. No relationship between training and accidents was found. A principal components analysis (PCA) of the attitudes items produced a 'safe attitudes' factor. Girls displayed 'safer' attitudes, but there was no evidence that training produced safer attitudes. A PCA of the cycling behaviour scales produced two factors, 'safe cycling' and 'showing off'. Safe cyclists who obeyed basic safety rules were less likely to sustain cycle injuries, but showing off was not related to accidents. Girls were less likely to show off, but the safe behaviour gender difference did not reach significance. Training did not relate to either factor. 相似文献