全文获取类型
收费全文 | 239篇 |
免费 | 9篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 48篇 |
金属工艺 | 1篇 |
建筑科学 | 19篇 |
矿业工程 | 2篇 |
能源动力 | 29篇 |
轻工业 | 15篇 |
水利工程 | 6篇 |
无线电 | 13篇 |
一般工业技术 | 28篇 |
冶金工业 | 18篇 |
原子能技术 | 2篇 |
自动化技术 | 57篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 19篇 |
2012年 | 14篇 |
2011年 | 19篇 |
2010年 | 19篇 |
2009年 | 23篇 |
2008年 | 11篇 |
2007年 | 10篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有248条查询结果,搜索用时 15 毫秒
21.
‘Real-Time’ is one of the most frequent concepts used referring to digital media. Despite it is commonly related to immediate feedback, it is not clear when it happens and what its characteristics are, especially in current digital interfaces. Although real-time has been written about very extensively in the context of Human Computer Interaction and Computational Systems, there are few studies evaluating the key features of real-time interaction in other domains. This article attempts to address this situation by proposing a new approach to the concept of real-time interaction driving the analysis of this topic into paradigmatic cases studies in new media, video games and digital artworks. This new analysis reveals several specific facets that allow us to identify new factors in the understanding of this fuzzy concept. Finally, the article proposes a new definition of ‘real-time interaction’ based on the findings in the context of new media practices. 相似文献
22.
Paolo Gronchi Roberto Canziani Andrea Brenna Simone Visigalli Carles Colominas Francesc Montalà 《Materials and Manufacturing Processes》2017,32(11):1265-1273
The sewage sludge dewatering produced by wastewater treatment plants (WWTP) is a multifaceted process due to the presence of colloid fractions. Electro-osmosis could be a suitable technique to reduce the water content of the final sludge. Electric fields of 10, 15, and 20?V/cm have been studied for electro-osmosis tests under the pressure of a static or rotating piston, obtaining a dry solids content up to 40–45%, with respect to 25–30% obtained by mechanical methods. In order to optimize the process, the corrosion behavior and the wear of the anodic material appear to be the main critical aspects, due to the high circulating current density and the use of a rotating electrode. We compared the efficiency and the corrosion resistance of dimensionally stable anodes (DSA) with respect to bare stainless steel (AISI 304) and stainless steel coated by PVD technique with TiN, AlTiN, and DLC. Characterization of the anode surfaces by SEM and potentiodynamic tests show that DSA is the most suitable material for our application. However, efficiencies of the electro-osmosis processes have been found comparable, in terms of developed current densities and total energy consumptions, for short-test duration. 相似文献
23.
The geometry optimization of a piezoresistive Twin-mass accelerometer is presented. The Twin-mass design is the most sensitive design to the stresses of the package compared to the Cantilever beam and the Quad-beam designs. Finite element simulations are carried out to improve the geometry of the Twin-mass design. Substitution of the perpendicular external beams by lateral external beams reduces the effects of the stresses of the package by a factor of more than 40. Moreover, the sensitivity and the figure of merit of the device can be easily increased. 相似文献
24.
Countercurrent reactor design and flowsheet for iodine-sulfur thermochemical water splitting process
Jean Leybros Philippe Carles Jean-Marc Borgard 《International Journal of Hydrogen Energy》2009,34(22):9060-9075
A conceptual design is presented for the I/S process for the production of hydrogen using a high-temperature nuclear heat source to split water. The process includes a countercurrent reactor being developed by CEA within the framework of an international collaboration (I-NERI project) with DOE at General Atomics (San Diego, CA). A ProsimPlus? model of the flowsheet indicates 600 kJ high-temperature heat and 69 kJ electric power are consumed per mole of H2 product (with an assumed pressure of 120 bars). The net thermal efficiency would be 38% (HHV basis) if electric power is available at a conversion efficiency of 45%. 相似文献
25.
26.
Esteve Fernández Anna Schiaffino Carme Borrell Joan Benach Carles Ariza Josep Maria Ramon Jorge Twose Manel Nebot Anton Kunst 《Nicotine & tobacco research》2006,8(1):29-36
Our objective was to examine social class and educational differences in long-term smoking cessation success among a cohort of smokers attending a specialized smoking clinic. We studied sustained abstinence after cessation among 1,516 smokers (895 men and 621 women) treated for smoking cessation between 1995 and 2001 at a university teaching hospital in the metropolitan area of Barcelona, Spain. We calculated 1-year and long-term (up to 8-year) abstinence probabilities by means of Kaplan-Meier curves and the hazard ratio of relapse by means of Cox regression, after adjusting for other predictors of relapse. Overall abstinence probability was .277 (95% CI = .254-.301). Men and women in social classes IV-V had significant hazard ratios of relapse after long-term follow-up (men: 1.36, 95% CI = 1.07-1.72; women: 1.60, 95% CI = 1.24-2.06), as compared with patients in social classes I-II. The same independent effect was observed for education: Men and women with primary or less than primary studies had higher hazard ratios of relapse (men: 1.75, 95% CI = 1.35-2.25; women: 1.92, 95% CI = 1.51-2.46), as compared with patients with a university degree. Similar estimates were obtained after adjustment for stage of change, Fagerstr?m score for nicotine dependence, and type of treatment. Patients of lower socioeconomic status are at higher risk of relapse, and this association is independent of other well-known predictors of relapse. Social differences have to be taken into account in the clinical setting when tailoring specific actions to treat smoking dependence. 相似文献
27.
Andrea H. Henseler Carles Ayats Miquel A. Perics 《Advanced Synthesis \u0026amp; Catalysis》2014,356(8):1795-1802
A series of primary amino acids covalently supported onto polystyrene through alkyne–azide cycloaddition reactions has been synthesized and evaluated as catalysts in asymmetric aldol reactions. A polymer‐supported threonine behaves as an easily recyclable, highly reactive and stereoselective (up to 99% ee) catalyst in the aldol reaction of both cyclic and acyclic ketone donors with aromatic aldehydes in aqueous environments. While cyclic ketones react with anti diastereoselectivity, syn adducts are predominantly obtained with acyclic substrates. The heterogenized threonine catalyst has been used for the sequential synthesis of a small library of enantiopure aldol products.
28.
针对大规模多入多出(MIMO)系统上行链路非平稳空间相关信道的估计问题,该文利用信道的时间-空间2维稀疏结构信息,应用狄利克雷过程(DP)和变分贝叶斯推理(VBI),设计了一种低导频开销和计算复杂度的信道估计迭代算法,提高了信道估计精度。由于平稳空间相关信道难以适用于大规模MIMO系统,该文借助于狄利克雷过程构建了非平稳空间相关信道先验模型,可将具有空间关联的多个物理信道映射为具有相同时延结构的概率信道,并应用变分贝叶斯推理设计了低导频开销和计算复杂度的信道估计迭代算法。实验结果验证了所提算法的有效性,且具有对系统关键参数鲁棒性的优点。
相似文献29.
G Roger P Carles B Pangon HV Thien JM Polonovski P Begue EN Garabedian 《Canadian Metallurgical Quarterly》1998,17(7):631-638
OBJECTIVES: To assess the clinical outcome and risk of failure after oral vs. intravenous treatment in otitis media caused by penicillin-resistant pneumococci. To determine the possible correlations between pneumococcal minimal inhibitory concentration (MIC) to penicillin and clinical outcome. DESIGN: Retrospective study of 156 cases collected between 1993 and 1995. Mean follow-up: 5 months. Setting. Two tertiary academic medical centers in Paris, France. PATIENTS AND METHODS: Pneumococcus was isolated from 191 of 570 ear samples obtained from children with otitis media and shown to be penicillin-resistant in 156. Medical history, antibiotic therapy during the previous 3 months and day-care center attendance were reviewed. For the current episode microbiologic characteristics of the isolated strains, type of treatment, therapy efficacy and clinical outcome were analyzed. Patients were predominantly young (76.3% were <1 year old) and bacteriologic samples were taken mainly because of previous treatment failure. RESULTS: Among 156 children with pneumococcal penicillin-resistant otitis media, 72.2% attended day-care centers, 71.8% had been previously treated with aminopenicillin and 52.5% with cephalosporins. Failure of previous empirical oral therapy was noted in 84% (one-third of these had been receiving amoxicillin-clavulanate). Patients treated intravenously had had a more protracted otitis but no greater number of previous episodes of acute otitis media than those receiving oral therapy. Acute mastoiditis occurred in 4 infants resulting in mastoidectomy. Oral treatment (mainly with high dose amoxicillin,120 to 150 mg/kg/day) and intravenous therapy (cephalosporin or glycopeptide) had been used in 59 and 41%, respectively. Mean duration of therapy was 10.7 days. Three failures (1.9%) and 10 recurrences (6.4%, average 28 days) occurred. No statistical difference was found between intravenous and oral therapy with respect to risk of recurrence. A high penicillin MIC value was correlated with previous antibiotic treatment but not with clinical outcome. CONCLUSIONS: Oral therapy appears to be as effective as intravenous therapy for the treatment of penicillin-resistant pneumococcal otitis media. Intravenous treatment should not necessarily be dictated by the penicillin susceptibility value but should be considered in cases of failure to thrive, persistent otitis or other complications. 相似文献
30.
From a study of the conductivity and photoconductivity of amorphous Se layers we are able to propose a model for the electronic states in the band gap. 相似文献