全文获取类型
收费全文 | 612篇 |
免费 | 29篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 34篇 |
综合类 | 1篇 |
化学工业 | 169篇 |
金属工艺 | 21篇 |
机械仪表 | 17篇 |
建筑科学 | 36篇 |
矿业工程 | 1篇 |
能源动力 | 15篇 |
轻工业 | 50篇 |
水利工程 | 2篇 |
无线电 | 39篇 |
一般工业技术 | 81篇 |
冶金工业 | 93篇 |
原子能技术 | 13篇 |
自动化技术 | 70篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 28篇 |
2021年 | 40篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 25篇 |
2017年 | 17篇 |
2016年 | 20篇 |
2015年 | 14篇 |
2014年 | 23篇 |
2013年 | 38篇 |
2012年 | 28篇 |
2011年 | 38篇 |
2010年 | 32篇 |
2009年 | 34篇 |
2008年 | 28篇 |
2007年 | 25篇 |
2006年 | 18篇 |
2005年 | 12篇 |
2004年 | 10篇 |
2003年 | 14篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 19篇 |
1999年 | 6篇 |
1998年 | 40篇 |
1997年 | 14篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 4篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1969年 | 1篇 |
排序方式: 共有642条查询结果,搜索用时 15 毫秒
101.
102.
Andrzej Klimpel Damian Janicki Aleksander Lisiecki Ziemowit Wilk Marek Burda Andrzej St. Klimpel 《Welding International》2013,27(6):495-500
The course of investigations on the development of technological conditions of manual and automatic repair plasma welding of cracks in the nozzle set of the TW2-117 engine turbine of the MI-8 helicopter made of EI 835(24-16-6) creep-resisting austenitic steel is described. Liquid-penetrant inspection and metallographic examination have shown a high quality of repair joints. 相似文献
103.
G. Bonheure G. Van Wassenhove M. Hult R. González de Orduña D. Strivay P. Vermaercke T. Delvigne G. Chene R. Delhalle A. Huber B. Schweer G. Esser W. Biel O. Neubauer 《Fusion Engineering and Design》2013,88(6-8):533-536
Fusion alpha particle diagnostics for ITER remain a challenging task. Standard escaping alpha particle detectors in present tokamaks are not applicable to ITER and techniques suitable for fusion reactor conditions need further research and development [1], [2]. The activation technique is widely used for the characterization of high fluence rates inside neutron reactors. Tokamak applications of the neutron activation technique are already well developed [3] whereas measuring escaping ions using this technique is a novel fusion plasma diagnostic development. Despite low alpha particle fluence levels in present tokamaks, promising results using activation technique combined with ultra-low level gamma-ray spectrometry [4] were achieved before in JET [5], [6].In this research work, we use new advanced detector materials. The material properties beneficial for alpha induced activation are (i) moderate neutron cross-sections (ii) ultra-high purity which reduces neutron-induced background activation and (iii) isotopic tailoring which increases the activation yield of the measured activation product.Two samples were obtained from GERDA[7], an experiment aimed at measuring the neutrinoless double beta decay in 76Ge. These samples, made of highly pure (9 N) germanium highly enriched to 87% in isotope Ge-76, were irradiated in real D–D fusion plasma conditions inside the TEXTOR tokamak. Comparison of the calculated and the experimentally measured activity shows good agreement. Compared to previously investigated high temperature ceramic material [8], this candidate detector offers better prospects for signal to background S/B ratio, energy resolution and particle selectivity due to a unique alpha particle signature. Applicability to ITER is discussed. Finally, research needs for further development of this diagnostic technique are outlined. 相似文献
104.
S. Kannan F. Goetz-Neunhoeffer J. Neubauer J. M. F. Ferreira 《Journal of the American Ceramic Society》2008,91(1):1-12
The structural information on the influence of ionic additions in biphasic (hydroxyapatite (HAP) and β-tricalciumphosphate (β-TCP)) mixtures ranging from single ionic substitutions to combined ionic substitutions of most of the essential ions embedded in biological apatite was analyzed through the Rietveld refinement technique. The results have proved that the determined quantitative phase composition of HAP and β-TCP in biphasic mixtures was dependent on the initial calcium (Ca) deficiency of the precursor powders precipitated from the different molar concentrations used in the synthesis. The substitution of cations (Na+ , Mg2+ , and K+ ) improved the stabilization of the β-TCP structure whereas anions (F− and Cl− ) were found incorporated at the OH− site of the HAP phase. Rietveld analysis of X-ray powder diffraction data from the present study proved to be a powerful technique to describe the position and occupancy of certain ions like Mg2+ and Cl− in the biphasic mixtures. However, it has also shown limitations in tracking back other ions like Na+ , K+ , and F− , which require the use of other complementary characterization methods. 相似文献
105.
Lauren Bloomfield Elizabeth Lane Madhur Mangalam Damian G. Kelty-Stephen 《Journal of the Royal Society Interface》2021,18(181)
Speech perception and memory for speech require active engagement. Gestural theories have emphasized mainly the effect of speaker''s movements on speech perception. They fail to address the effects of listener movement, focusing on communication as a boundary condition constraining movement among interlocutors. The present work attempts to break new ground by using multifractal geometry of physical movement as a common currency for supporting both sides of the speaker–listener dyads. Participants self-paced their listening to a narrative, after which they completed a test of memory querying their narrative comprehension and their ability to recognize words from the story. The multifractal evidence of nonlinear interactions across timescales predicted the fluency of speech perception. Self-pacing movements that enabled listeners to control the presentation of speech sounds constituted a rich exploratory process. The multifractal nonlinearity of this exploration supported several aspects of memory for the perceived spoken language. These findings extend the role of multifractal geometry in the speaker''s movements to the narrative case of speech perception. In addition to posing novel basic research questions, these findings make a compelling case for calibrating multifractal structure in text-to-speech synthesizers for better perception and memory of speech. 相似文献
106.
Skiba G Raj S Poławska E Pastuszewska B Elminowska-Wenda G Bogucka J Knecht D 《Meat science》2012,91(3):339-346
Forty-eight gilts were submitted to a 30% restriction of feed (groups F and F1) or protein intake (group P) from 90 to 118 days of age, followed by realimentation from 119 to 168 days of age. Control pigs (C) were fed during the whole experiment according to a semi ad libitum scale. During realimentation all animals were fed according to semi ad libitum scale except pigs F1 which were fed ad libitum. Six pigs from each group were slaughtered at the end of restriction and realimentation. Restriction decreased the weight of musculus longissimus dorsi (MLD) and increased shear force. Restriction of feed intake depressed MUFA concentration and increased n-6/n-3 ratio while protein restriction decreased n-6/n-3 and PUFA:SFA ratios. Structure of fibers was not affected. After realimentation MLD mass was still lower in all previously restricted pigs, shear force was the lowest in F1 pigs. Only percentage of fast twich oxidative fibers was significantly greater in F1 pigs than in others. Significant correlations between parameters investigated during the study were found. 相似文献
107.
Results from natural and engineered phytoremediation systems provide strong evidencethatvegetated soils mitigate polycyclic aromatic hydrocarbon (PAH) contamination. However, the mechanisms by which PAH mitigation occurs and the impact of plant organic matter on PAH attenuation remain unclear. This study assessed the impact of plant organic matter on PAH attenuation in labile and refractory sediments fractions from a petroleum distillate waste pit that has naturally revegetated. Samples were collected in distinct zones of barren and vegetated areas to assess changes to organic matter composition and PAH content as vegetation colonized and became established in the waste pit. Sediments were fractionated into bulk sediment and humin fractions and analyzed for organic matter composition by isotope ratio mass spectrometry (delta (13)C), 13C nuclear magnetic resonance (13C NMR), delta 14C AMS (accelerator mass spectrometry), and percent organic carbon (%TOC). Gas chromatography mass spectrometry (GC/ MS) of lipid extracts of SOM fractions provided data for PAH distribution histograms, compound weathering ratios, and alkylated and nonalkylated PAH concentrations. Inputs of biogenic plant carbon, PAH weathering, and declines in PAH concentrations are most evidentfor vegetated SOM fractions, particularly humin fractions. Sequestered PAH metabolites were also observed in vegetated humin. These results show that plant organic matter does impact PAH attenuation in both labile and refractory fractions of petroleum distillate waste. 相似文献
108.
Dr. Katja Neubauer Udo Lubenau Christine Hecker Prof. Dr. Bernhard Lücke Dr. Dietmar Paschek Dr. Sebastian Wohlrab 《化学,工程师,技术》2013,85(5):713-722
The depletion of higher alkanes from methane is a key aspect during the conditioning of natural gases or accompanying gases. Membrane technologies could be used as alternative to energy and cost intensive purifications. Against this background the influence of membrane geometry, composition of the gas mixture as well as temperature and pressure was investigated in separation experiments for methane/n‐butane mixtures using MFI membranes. 相似文献
109.
110.