全文获取类型
收费全文 | 292篇 |
免费 | 15篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 77篇 |
金属工艺 | 7篇 |
机械仪表 | 10篇 |
建筑科学 | 13篇 |
能源动力 | 25篇 |
轻工业 | 28篇 |
水利工程 | 1篇 |
无线电 | 51篇 |
一般工业技术 | 44篇 |
冶金工业 | 4篇 |
原子能技术 | 1篇 |
自动化技术 | 46篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 14篇 |
2020年 | 17篇 |
2019年 | 15篇 |
2018年 | 17篇 |
2017年 | 19篇 |
2016年 | 14篇 |
2015年 | 9篇 |
2014年 | 17篇 |
2013年 | 31篇 |
2012年 | 15篇 |
2011年 | 16篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 21篇 |
2007年 | 12篇 |
2006年 | 5篇 |
2005年 | 14篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有311条查询结果,搜索用时 15 毫秒
101.
Nowadays, healthcare applications become among the most important services that help to improve the public safety through, for example, the prevention of the propagation of some epidemic diseases from patient to another or better from a location to another. Wireless Body Area Networks (WBANs) are considered among the major sources that enable the collection of such kind of data that shares in most cases the properties of big data and that needs to be stored and managed in an efficient manner. Regarding this need, Wireless Storage Area Networks (WSANs) have been considered among the alternatives to store generated health data. Even if these infrastructures enable the storage of huge volumes of data, there are some issues related to the efficient storage and processing of health data that still not resolved and that are of interest for the research communities. In this context, this paper proposes a cloud-based WSAN approach that enables the storage and the management of health data in an efficient manner by representing the collected data and their dependencies using Temporal Conceptual Graphs (TCGs). The validity of the generated graphs is verified by the proposed graph checker that enables the localization of semantic errors in such structure to prevent some threats to be realized for stored health data and to ensure the privacy of patients. The efficiency of the proposed approach is illustrated for different defined scenarios of diseases and their associated health data represented through generated TCGs. 相似文献
102.
103.
104.
Mayouf Sellami Vincent Caignaert Meriem Hamdad Ahmed Bekka Noureddine Bettahar 《Journal of Alloys and Compounds》2009,482(1-2):13-18
A new pyrochlore solid solution with formula Bi1.5Sb1.5Cu1−xMnxO7 has been synthesized using ceramic method at 1000 °C. The cell parameter decreases linearly with increasing manganese concentration. Rietveld refinements for (B1.5Mn0.5)(Sb1.5Mn0.5)O7 compound using X-ray powder diffraction data confirmed an overall A2B2O7 cubic pyrochlore structure with a = 10.42749 (4) Å and Fd-3m symmetry. The reliability factors are Rwp = 3.48%; Rp = 2.37%; Rexp = 1.65% and RBragg = 1.58%. The magnetic susceptibility measurements achieved between 4 and 300 K indicate a paramagnetic behaviour with an oxidation state “2+” of the manganese ion. The electric resistance measured using complex impedance spectroscopy method put in evidence a decrease of the electric resistance with the temperature, which reached 5 × 102 Ω at 675 K. Dielectric properties depend on the variation of frequency and temperature, results indicate a conductive compound. 相似文献
105.
Noureddine Benkeblia Patrick Varoquaux Norio Shiomi & Hideki Sakai 《International Journal of Food Science & Technology》2002,37(2):169-175
The effects of γ-irradiation, maleic hydrazide (MH) and carbamate isopropyl, N-phenyl (CIP) on the carbohydrate content, respiration rate (RR) sprouting and rotting of red onion bulbs ( Allium cepa L.) c.v. Rouge Amposta stored at 4, 10 and 20 °C were investigated. Between 6 and 8 weeks soluble sugars increased in concentration and varied between 6.0 and 6.5% fresh weight both at 10 and 20 °C. However, this peak did not exceed 6.0% fresh weight at 4 °C. The basal amount of soluble sugars was about 3% fresh weight. The content appeared to be influenced by temperature, with greater accumulation at 10 and 20 °C than at 4 °C. The RR increased when the bulbs sprouted, whereas it was reduced by the following treatments: irradiation, MH and CIP, the respiration of irradiated bulbs decreased during the final stage of storage because of the death of the sprouts. The chemical treatment used were effective in controlling sprouting of the bulbs during storage, although not as effective as irradiation and chilling. 相似文献
106.
Quang Hung Tran Morvan Ouisse Noureddine Bouhaddi 《Mechanical Systems and Signal Processing》2010,24(1):164-181
In order to reduce vibrations or sound levels in industrial vibroacoustic problems, the low-cost and efficient way consists in introducing visco- and poro-elastic materials either on the structure or on cavity walls. Depending on the frequency range of interest, several numerical approaches can be used to estimate the behavior of the coupled problem. In the context of low frequency applications related to acoustic cavities with surrounding vibrating structures, the finite elements method (FEM) is one of the most efficient techniques. Nevertheless, industrial problems lead to large FE models which are time-consuming in updating or optimization processes. A classical way to reduce calculation time is the component mode synthesis (CMS) method, whose classical formulation is not always efficient to predict dynamical behavior of structures including visco-elastic and/or poro-elastic patches. Then, to ensure an efficient prediction, the fluid and structural bases used for the model reduction need to be updated as a result of changes in a parametric optimization procedure. For complex models, this leads to prohibitive numerical costs in the optimization phase or for management and propagation of uncertainties in the stochastic vibroacoustic problem. In this paper, the formulation of an alternative CMS method is proposed and compared to classical (u,p) CMS method: the Ritz basis is completed with static residuals associated to visco-elastic and poro-elastic behaviors. This basis is also enriched by the static response of residual forces due to structural modifications, resulting in a so-called robust basis, also adapted to Monte Carlo simulations for uncertainties propagation using reduced models. 相似文献
107.
Riad Ladji Noureddine Yassaa Catia Balducci Brahim Youcef Meklati 《The Science of the total environment》2009,408(2):415-424
The distribution of the solvent-extractable organic components in the fine (PM1) and coarse (PM1-10) fractions of airborne particulate was studied for the first time in Algeria. That was done during October 2006 concurrently in a big industrial district, a busy urban area, and a forest national park located in Algiers, Boumerdes, Blida, respectively, which are the three biggest provinces of Northern Algeria. Most of the organic matter identified in both particle size ranges consisted of n-alkanes and n-alkanoic acids, with minor contributions coming from polycyclic aromatic hydrocarbons (PAHs), nitrated polycyclic aromatic hydrocarbons (NPAHs), oxygenated PAHs, and other polar compounds (e.g., caffeine and nicotine). The potential emission sources of airborne contaminants were reconciled by combining the values of n-alkane carbon preference index (CPI) and selected diagnostic ratios of PAHs, calculated in both size ranges. The mean cumulative concentrations of PAHs reached 3.032 ng m− 3 at the Boumerdes site, urban, 80% of which (i.e. 2.246 ng m− 3) in the PM1 fraction, 6.462 ng m− 3 at Rouiba-Réghaia, industrial district, (5.135 ng m− 3 or 80% in PM1), and 0.512 ng m− 3 at Chréa, forested mountains (0.370 ng m− 3 or 72% in PM1). Similar patterns were shown by all organic groups, which resulted overall enriched in the fine particles at the three sites. Carcinogenic and mutagenic potencies associated to PAHs were evaluated by multiplying the concentrations of “toxic” compounds times the corresponding potency factors normalized vs. benzo(a)pyrene (BaP), and were found to be both acceptable. 相似文献
108.
Noureddine Rhayma Pierre Breul Patrick Goirand 《Structure and Infrastructure Engineering》2016,12(3):381-393
The current mechanical investigation strategy applied to RATP (Régie Autonome des Transpots Parisiens) tunnels is mainly based on visual inspection. All the works are inspected and every apparent fault is located and reported in inspection reports. However, this type of inspection detects only apparent faults without linking them to their causes. A new methodology of mechanical investigation is proposed in the framework of the ANR project MEDITOSS (Méthodologie de Diagnostic des Tunnels et Ouvrages Souterrains en Service), consisting in integrating mechanical investigation tools to better characterise the geometrical and mechanical state of the tunnel. This new strategy combines four techniques (ground penetrating radar, light dynamic penetrometer, endoscopy and geo-mechanical impedance). These techniques are applied to panels to obtain a ‘panel score’. This paper presents a risk analysis of the system studied (network of corridors and tunnels), by applying the bow-tie method in order to obtain information on its elements, its function and its pathologies. This analysis incorporates a quantitative characterisation method (scoring) to assess the state of corridors and tunnels. These methods are tested on infiltration and cracking pathologies for the risk analysis and on the notation of a corridor for the quantitative quantification. 相似文献
109.
Development of polylactide open‐cell foams with bimodal structure for high‐acoustic absorption 下载免费PDF全文
In this study, a highly porous and interconnected foam structure was fabricated using compression molding combined with particulate‐leaching technique. The foamed structures were fabricated with polylactide (PLA) and polyethylene glycol (PEG) with salt as the particulate. The pore size of the foam structure is controlled by the particulates size and higher interconnectivity is achieved by the co‐continuous blending morphology of the PLA matrix with the water‐soluble PEG. PLA is a fully bio‐based thermoplastic polymer and is derived from renewable resources, such as cornstarch or sugarcanes. PEG is also fully biodegradable polymer produced from ethylene. Fabricated foams were characterized for cellular, acoustic, and mechanical properties. The acoustic performance of the foams was studied by measuring the normal incident absorption coefficient in accordance with the ASTM E1050 standard. The results show open porosity as high as 88% was achieved and the effect of water‐soluble polymer on cellular properties and acoustic and mechanical performance of the foams was studied. As a result of the secondary porous structure formed into cell walls by water soluble polymer, the overall absorption of fabricated PLA foams was increased to above 90% while the average absorption of the foams remained unchanged. In addition, the resulting acoustic foams are benign and environmentally friendly. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39518. 相似文献
110.
Joseph Z. Su Noureddine Bénichou Alex Bwalya Gary Lougheed Bruce Taber Patrice Leroux 《Fire Technology》2011,47(3):631-664
A full-scale experimental program was undertaken to study the impact of two basement fire scenarios on the structural integrity
of unprotected floor assemblies above a basement and the tenability conditions in a test facility representing a typical two-storey
detached single-family house with a basement. The experiments utilized relatively severe, fast-growing fires set in the basement,
which had an unprotected (unfinished) ceiling, to challenge the structural integrity of the floor system above the basement,
which provides the normal egress route on the first storey for occupants. A range of floor assemblies constructed with various
types of engineered floor joists and trusses (including wood I-joists, steel C-joists, metal plate wood trusses and metal
web wood trusses) and with solid-wood joists, were used in the experiments with the basement side unprotected (unsheathed).
Potential exposure to toxic gases, heat and smoke obscuration under the test conditions was analyzed to estimate the time
available for escape. The results help establish the sequence of fire events such as fire initiation, smoke alarm activation,
onset of untenable conditions, and structural failure of the floor assembly above the basement to understand how these factors
affect the ability of occupants on the upper storeys to escape in the event of a basement fire. 相似文献