全文获取类型
收费全文 | 177篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 45篇 |
金属工艺 | 2篇 |
机械仪表 | 6篇 |
建筑科学 | 10篇 |
能源动力 | 15篇 |
轻工业 | 23篇 |
水利工程 | 5篇 |
石油天然气 | 1篇 |
无线电 | 14篇 |
一般工业技术 | 30篇 |
冶金工业 | 10篇 |
原子能技术 | 2篇 |
自动化技术 | 29篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 17篇 |
2021年 | 13篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 17篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 21篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 3篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1991年 | 2篇 |
1985年 | 1篇 |
1979年 | 2篇 |
排序方式: 共有192条查询结果,搜索用时 15 毫秒
1.
Conductance measurements are reported for s-alkylisothiouronium bromide, iodide and picrate salts in the dipolar aprotic solvent DMSO at 25°C. The data were analysed by Fuoss's equation (1975–1980) for 1:1 electrolytes, from which the values of Λ0, the Gurney's cosphere diameter R and KA are obtained. The results are discussed in the light of the recorded values of the constants KR and KS and the free energy term Gs. 相似文献
2.
Amina Ghedjemis Riad Ayeche Ali Benouadah Noureddine Fenineche 《International Journal of Applied Ceramic Technology》2021,18(3):590-597
The aim of this paper is to evaluate the efficiency of the natural hydroxyapatite powder for anionic dye (Congo red) elimination from water and optimization of adsorption process parameters that are contact time (0-360 min), solution pH (4-9), initial dye concentration (400-2400 mg/l), and adsorbent dosage (0.4-20 g/l). Natural hydroxyapatite with high surface area was prepared from animal agriculture waste dromedary bone. X-ray diffraction, transmission electron microscopy, transform infrared spectroscopy, and elemental analysis characterizations of the powder prepared show a hexagonal structure, the irregular form of hydroxyapatite and presence of other elements as trace element. The results of adsorption tests demonstrated the high efficiency of natural hydroxyapatite for removal of Congo red from water solution whose maximum experimental capacity adsorption of Congo red by natural hydroxyapatite is 900 mg/g at pH 4.5, equilibrium time 240 min and adsorbent dosage 2 g/l. According to the correlation coefficient value, the pseudo-second order kinetic model identified the sorption mechanism of pollutant used on natural hydroxyapatite. The Freundlich isotherm is the best representative theoretical model of the dye molecules’ adsorption on the natural hydroxyapatite support. 相似文献
3.
Fatima Boumahdi Rachid Chalal Amina Guendouz Khalida Gasmia 《Service Oriented Computing and Applications》2016,10(1):35-53
In recent years, Service Oriented Architecture (SOA) technologies are emerging as a powerful vehicle for organizations that need to integrate their applications within and across organizational boundaries. In addition, organizations need to make better decisions more quickly. Moreover, they need to change those decisions immediately to adapt to this increasingly dynamic business environment. It is primarily a question in ensuring the decisional aspect by adopting the SOA as a support architecture. In this paper, we describe a new approach called SOA\(^\mathrm{+d}\) based on a certain number of standards. It is going to be studied on three dimensions: The first is related to the definition of the information system implied in the SOA based on the use case model. The second develops the business dimension which is based on the BPMN (Business Process Modeling Notation). The last dimension addresses the need of decision; we use the new standard decision model and notation (DMN) which is recently approved by Object Management Group (OMG) and considered as a simple notation to specify the decision. Finally, Service Oriented Architecture Modeling Language (SoaML) will be used for design of several services. We also present our meta-model Decisional Model of Service (DMS) to define a new set of concepts necessary for modeling the three levels. Some of them are already known, whereas others are new and are proposed as an element of this work. we illustrate our proposal with a real case study in the Pharmacy Inventory Management. 相似文献
4.
Amina L. Mohamed Mehrez E. El-Naggar Tharwat I. Shaheen Ahmed G. Hassabo 《Microsystem Technologies》2016,22(5):979-992
An innovative strategy for functional finishing of cellulosic based materials is based on the incorporation of a thin layer of surface modifying systems (SMS) in the form of stimuli-sensitive nanogels containing combining metal nanoparticles and silica. The silver–silica core–shell nanoparticles (NPs) were synthesized by simple one pot chemical method. Silica/silver nanoparticles have been synthesized using low concentration of dextran as reducing and stabilizing agent and using ascorbic acid as antioxidant agent. The core–shell NPs were characterized for their structural, morphological, compositional and optical behaviour using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. Stimuli-responsive nanogel was prepared by copolymerization of poly(N-isopropylacrylamide) with pullulan, results in a nanogel that is responsive to both temperature and pH, the nano-particulate hydrogel of poly-NiPAAm-pullulan copolymer was synthesized using surfactant-free emulsion method. The prepared nano-particles were used during the preparation steps of the pullulan nanogel to obtain nanogel/combining metal/silica NPs to produce a composite materials. The nanoparticle size in dry (collapsed) state is estimated at 250 nm by SEM and TEM, and effect of temperature and pH on gel-nanoparticles was investigated by DLS and UV–vis spectrophotometry. The incorporation of the nanoparticles to cellulosic material was done by a simple pad dry-cure procedure from aqueous nanoparticle dispersion that contained a cross-linking agent. This application method provided sufficient integrity to coating by maintaining the responsiveness of surface modifying system. The stimuli responsiveness of modified cellulosic materials has been confirmed in terms of regulating its water uptake in dependence of pH and temperature. 相似文献
5.
Amina Mseddi Khouloud Wali Ahmed Abid Omar Naifar Mohamed Rhaima Lassaad Mchiri 《Asian journal of control》2024,26(3):1103-1119
The focus of this study is on modeling and management of a Wind Energy Conversion System (WECS) based on a Hybrid Excitation Synchronous Generator (HESG). Using a wind simulator, two controllers, CRONE and H∞, are evaluated for Maximum Power Point Tracking (MPPT) and optimal rotation speed. The results show the CRONE controller's higher tracking capability, and robustness tests investigate the influence of parametric uncertainty. Space harmonic effects, commutation effects, and turbine shaft flexibility are all addressed in the sophisticated models. The introduction of Fractional Order Proportional-Integral (FOPI) control for MPPT is a game changer. Although fractional calculus-based accuracy and robustness are uncommon in WECS, they show promise for emissions reduction and increased energy efficiency. This work validates a dependable control approach inside an isolated HESG-based WECS's power-maximizing range. Extensive investigation of the parameters impacting FOPI control efficiency yields useful insights for effective MPPT control. A variable-speed wind turbine (WT) is linked to a HESG through a multiplier, with a controller controlling generator coil excitation voltages and a rectifier connecting the WECS to a load. A thorough 3 kW HESG electrical model that includes generator space harmonics and converter commutation effects is among the contributions. For HESG-based WECS stability, frequency analysis finds important resonant and anti-resonant frequencies. These issues are addressed by a FOPI control technique, which ensures system stability and performance. The necessity of exact frequency analysis in HESG-based WECS is highlighted by a step-by-step controller parameter tuning approach. 相似文献
6.
Lakshmy Rajesh Amina Al-Farsi 《The International journal of environmental studies》2017,74(6):979-990
The paper reports the first study of diversity and distribution of freshwater macrophytes in the wedian (plural of wadi = seasonal river) of the northern Al Hajar Mountain range in Oman. Fifteen lentic habitats in the wedian were surveyed. The number of species, their growth forms and abundance were recorded in the studied habitat of each wadi. In all, 41 species belonging to 14 families and 32 genera were collected. Of these 37 species were emergent and four were submergent. Poaceae was the most diverse emergent family with 17 species. Phragmites australis was the most common emergent followed by Typha domingensis. Among submerged macrophytes, Chara vulgaris had higher frequency of occurrence with low abundance followed by Potamogeton distinctus with relatively high abundance. Floristic diversity was estimated using species richness (Margalef’s D), general diversity (Shannon–Wiener H′), evenness (Pielous’s EH), and dominance (Berger–Parker d) indices for each study habitat. Principal component analysis was used to evaluate the variability using four indices. PC1 and PC2 explained 98.18% of the variability. Some habitats in different watersheds exhibited similar species diversity, but some in the same watershed were different. Baseline data on the freshwater macrophytes in northern Oman are provided here. 相似文献
7.
8.
9.
Muhammad G. Abd El-Moghny Hafsa H. Alalawy Ahmad M. Mohammad Amina A. Mazhar Mohamed S. El-Deab Bahgat E. El-Anadouli 《International Journal of Hydrogen Energy》2017,42(16):11166-11176
Research is moving rapidly to sustain convenient energy resources fulfilling the global climate legislations. Herein, a novel catalyst of platinum nanoparticles (PtNPs) dispersed onto polyaniline (PANi) is recommended for formic acid electro-oxidation (FAO); the fundamental anodic reaction in direct formic acid fuel cells (DFAFCs). The catalyst's preparation scheme allows a sequential electrodeposition of fibril PANi and spherical PtNPs (ca. 65 nm in size) on a glassy carbon (GC) substrate and permits a precise control over the deposition sequence and loading. Interestingly, incorporation of PANi into the catalyst's ingredients can significantly (ca. 16 times) improve the catalytic activity of the catalyst towards FAO by shifting the mechanism towards the desirable dehydrogenation pathway and mitigating the undesirable poisoning dehydration pathway. The catalytic efficiency is tuned by manipulating the deposition order and loading of different catalyst's ingredients. Several techniques are employed to confirm the successful deposition of the catalyst and to evaluate its morphology, composition and crystal structure. While PtNPs are essential for FA adsorption, PANi improves the dispersion of PtNPs and mediates FAO to facilitate the charge transfer and mitigate CO poisoning. A promising catalytic stability is achieved in a long continuous (150 CVs) electrolysis experiment. 相似文献