全文获取类型
收费全文 | 318篇 |
免费 | 18篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 1篇 |
综合类 | 2篇 |
化学工业 | 69篇 |
金属工艺 | 10篇 |
机械仪表 | 1篇 |
建筑科学 | 19篇 |
矿业工程 | 3篇 |
能源动力 | 9篇 |
轻工业 | 45篇 |
水利工程 | 5篇 |
石油天然气 | 6篇 |
无线电 | 25篇 |
一般工业技术 | 61篇 |
冶金工业 | 36篇 |
原子能技术 | 1篇 |
自动化技术 | 48篇 |
出版年
2023年 | 10篇 |
2022年 | 17篇 |
2021年 | 21篇 |
2020年 | 12篇 |
2019年 | 13篇 |
2018年 | 19篇 |
2017年 | 15篇 |
2016年 | 12篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 19篇 |
2012年 | 16篇 |
2011年 | 20篇 |
2010年 | 19篇 |
2009年 | 8篇 |
2008年 | 19篇 |
2007年 | 13篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有341条查询结果,搜索用时 924 毫秒
31.
Elsayed-Ali OH Abdel-Fattah T Elsayed-Ali HE 《Journal of hazardous materials》2011,185(2-3):1550-1557
Zeolites are used in environmental remediation of soil or water to immobilize or remove toxic materials by cation exchange. An experiment was conducted to test the use a low electric field to direct the toxic cations towards the zeolite. An electrokinetic cell was constructed using carbon electrodes. Synthetic Linde Type A (LTA) zeolite was placed in the cell. Copper(II) chloride dissolved in water was used as a contaminant. The Cu(2+) concentration was measured for ten hours with and without an applied electric field. The removal of the Cu(2+) ions was accelerated by the applied field in the first two hours. For longer time, the electric field did not improve the removal rate of the Cu(2+) ions. The presence of zeolite and applied electric field complicates the chemistry near the cathode and causes precipitation of Cu(2+) ions as copper oxide on the surface of the zeolite. With increased electric field the zeolite farther away from the cathode had little cation exchange due to the higher drift velocity of the Cu(2+) ions. The results also show that, in the LTA Zeolite A pellets, the cation exchange of Cu is limited to a shell of several tens of micrometers. 相似文献
32.
The aim of this work was to synthesis highly amorphous geopolymer from waste coal fly ash, to be used as an adsorbent for lead Pb(II) removal from aqueous wastewater. The effect of various parameters including geopolymer dosage, initial concentration, contact time, pH and temperature on lead adsorption were investigated. The major components of the used ash in the current study were SiO(2), Al(2)O(3) and Fe(2)O(3) representing 91.53 wt% of its mass. It was found that the synthesized geopolymer has higher removal capacity for lead ions when compared with that of raw coal fly ash. The removal efficiency increases with increasing geopolymer dosage, contact time, temperature, and the decrease of Pb(2+) initial concentration. The optimum removal efficiency was obtained at pH 5. Adsorption isotherm study indicated that Langmuir isotherm model is the best fit for the experimental data than Freundlich model. It was found also that the adsorption process is endothermic and more favorable at higher temperatures. 相似文献
33.
Heba Nashaat Rawya Rizk Hani Mahdi 《International Journal of Wireless Information Networks》2011,18(4):210-223
Mobile IP has been developed to provide the continuous information network access to mobile users. The performance of Mobile
IP mobility management scheme is dependent on traffic characteristics and user mobility. Consequently, it is important to
assess this performance in-depth through these factors. This paper introduces a novel analytical model of handoff management
in mobile IP networks. The proposed model focuses on the effect the traffic types and their frame error rates on the handoff
latency. It is derived based on general distribution of both successful transmission attempts and the residence time to be
applicable in all cases of traffic characteristics and user mobility. The impact of the behavior of wireless connection, cell
residence time, probability distribution of transmission time and the handoff time is investigated. Numerical results are
obtained and presented for both TCP and UDP traffics. As expected, the reliability of TCP leads to higher handoff latency
than UDP traffic. It is shown that, higher values of FER increase the probability of erroneous packet transfer across the
link layer. A short retransmission time leads to end the connection most likely in the existing FA; however a long retransmission
time leads to a large delivery time. The proposed model is robust in the sense that it covers the impact of all the effective
parameters and can be easily extended to any distribution. 相似文献
34.
Cedric Cocaud Aaron Price Amor Jnifene Hani Naguib 《International Journal of Mechanics and Materials in Design》2006,3(3):223-236
This paper presents a study on the potential application of artificial muscles based on shape memory alloys as linear robotic
actuators. An extended discussion on various control techniques and ways of biologically inspired muscle arrangements is presented.
A two DOF experimental robotic arm was built and used to test the performance of the proposed artificial muscle configurations,
and a biologically inspired control strategy using a rule-base concept was developed and tested using the two DOF experimental
robotic arm. 相似文献
35.
Thin films (30 to 80 nm) of refractory tantalum metal were successfully sputter-deposited on uniformly deformable fluoropolymer and polyimide substrates in stress free form. These films were later anodized into amorphous Ta2O5 which is a non-porous (barriertype) oxide with excellent corrosion resistant properties. X-ray photo-emission spectroscopy studies were carried out on tantalum and Ta2O5 to determine the chemical composition and oxidation states of elements. Thin tantalum and Ta2O5 films on fluoropolymer substrates contained fluorine as an impurity while similar films on polyimide substrate contained no fluorine and, in general, fewer impurities. Both thin tantalum films and the corresponding anodic oxides, when deformed in tension to 10% strain, exhibited the expected ductile behaviour of metals where slip bands were observed in the electron microscope. In some cases, minor cracks were observed in the deformed anodic films due to suspected local detachment of the film from the substrate. 相似文献
36.
Fernando M. Lan as Emanuel Carrilho Harold M. McNair Hani S. Karam 《Petroleum Science and Technology》1988,6(2):209-223
The quality, as well as the quantity of coal-derived liquids are Investigated using low-boiling extracting agents and mechanical stirring. A broad range of solvents with different boiling point and polarities are studied in order to generate the desired coal-derived material. Several experimental conditions are shown to be critical: the nature of solvent, solvent-to- coal ratio and the volume of washing solvent. The method is shown to be reliable for generating coal-derived products, since it is performed under mild experimental conditions and generates amounts of material comparable to Soxhlet extraction procedures in much less time. In addition, it is cheap, easy to perform, fast and reproducible. 相似文献
37.
Josee K. Perron Hani E. Naguib Joseph Daka Attar Chawla 《Polymer Engineering and Science》2009,49(10):2062-2069
This study presents a comprehensive parametric study on the effects of processing parameters on the poly(DL‐lactide‐co‐glycolide) acid (PLGA) 85/15 scaffold's physical properties. Porous PLGA 85/15 scaffolds were prepared using a gas foaming/salt leaching technique. The processing parameters under examination for the gas foaming/salt leaching method included: gas saturation pressure (SP), gas saturation time, and NaCl/polymer mass ratio (NaCl/PMR). The physical properties considered in this study were the scaffold density, the scaffold porosity, and the average pore size of the scaffold. Young's moduli in compression, as well as the pore density (PD) inside the scaffold, were also studied. The results demonstrated optimum correlations of processing parameters are required to produce a scaffold with a high level of interconnectivity. In general, all scaffolds yielded by this experiment exhibited a porosity more than 90%, a relative density ranging from 0.0534 to 0.149 g/cm3, a PD ranging from 1.51 × 106 to 6.72 × 106 pores/cm3, and a compressive modulus ranging from 0.07 to 0.84 MPa. It was determined that the NaCl/PMR was the parameter that had the most significant effect on the physical properties of the scaffold. The average pore size was affected slightly by the SP only, and it was observed that the pore size was equivalent to the size of the NaCl particles used to make the scaffold. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers 相似文献
38.
The present contribution was aimed to estimate the vaporization enthalpy of petroleum fractions and pure hydrocarbons by using the combination of adaptive neuro-fuzzy inference system (ANFIS) and genetic algorithm (GA) called GA-ANFIS. This tool can approximate the vaporization enthalpy as a function of the specific gravity, molecular weight, and boiling point temperature with high accuracy based on 122 data gathered from the previously published literature. Furthermore, results from the proposed model have been compared with different correlations and its acceptable predictive ability against other correlations was proved in order to the estimation of the vaporization enthalpy. The percentage of absolute relative deviation and R-squared (R2) was 1.64% and 0.9967%, respectively. This tool is simple to use and can be of considerable help for petroleum engineers to have an accurate estimation of vaporization enthalpy of hydrocarbon fractions of pure hydrocarbons. 相似文献
39.
40.
Ibdal Satar Mimi Hani Abu Bakar Wan Ramli Wan Daud Nazlina Haiza Mohd Yasin Mahendra Rao Somalu Byung Hong Kim 《国际能源研究杂志》2020,44(9):7464-7476
The low cost, low over-potential loss, good catalytic properties for hydrogen evolution reaction (HER), high corrosion stability, commercially available, and could be applied in pH-neutral solution and ambient temperature are important properties for the cathode materials when it is applied in microbial electrolysis cell (MEC) technology. This study has two-pronged objectives: the first is to investigate the feasibility of titanium (Ti) and graphite felt (GF) coated with nickel (Ni), and the second is to generate hydrogen from the fermentation effluent (FE). The electrodeposition (ED) method was used to deposit Ni catalyst onto Ti (Ni/Ti) and GF (Ni/GF) surfaces. The scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy were used to characterize the cathode morphology and element composition. The catalytic properties of Ni/Ti and Ni/GF could be evaluated using the linear sweep voltammetry tests. The maximum volumetric H2 production rates of MEC using Ni/Ti and Ni/GF cathodes were obtained at 0.39 ± 0.01 and 0.33 ± 0.03 m3 H2 m−3 d−1 respectively. The Ni/Ti and Ni/GF cathodes could be used as alternative cathodes while producing hydrogen from FE. 相似文献