全文获取类型
收费全文 | 300篇 |
免费 | 13篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 5篇 |
综合类 | 24篇 |
化学工业 | 46篇 |
金属工艺 | 11篇 |
机械仪表 | 22篇 |
建筑科学 | 16篇 |
能源动力 | 18篇 |
轻工业 | 18篇 |
无线电 | 40篇 |
一般工业技术 | 40篇 |
冶金工业 | 8篇 |
原子能技术 | 2篇 |
自动化技术 | 64篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 11篇 |
2017年 | 12篇 |
2016年 | 8篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 23篇 |
2012年 | 22篇 |
2011年 | 24篇 |
2010年 | 19篇 |
2009年 | 26篇 |
2008年 | 17篇 |
2007年 | 17篇 |
2006年 | 11篇 |
2005年 | 5篇 |
2004年 | 11篇 |
2003年 | 25篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有314条查询结果,搜索用时 15 毫秒
111.
Engin Burgaz 《Polymer》2011,52(22):5118-5126
Poly(ethylene-oxide) PEO/clay/silica nanocomposites were prepared via solution intercalation by exploiting phase separation based on the bridging of particles by polymer chains. The intercalated morphology of nanocomposites was confirmed by XRD. Vibrational modes of the ether oxygen of PEO in the hybrids are shifted due to the coordination of the ether oxygen with the sodium cations of clay and the H-bonding interactions of the ether oxygen with the surface silanols of hydrophilic fumed silica. Based on SEM, the overall density of nanoparticle aggregates in the interspherulitic region was observed to be higher compared to that inside spherulites. PEO/clay/silica hybrids show significant property improvements compared to PEO/clay hybrids and pure PEO. The system containing 10 wt.% clay and 5 wt.% silica has substantially higher modulus and much lower crystallinity compared to the 15 wt.% clay system. The physics behind the reinforcement effect and the reduction of crystallinity as a function of fumed silica loading is discussed based on the morphological characterization of the hybrids. Lastly, PEO/clay/silica hybrids display good thermal stability and are much stiffer compared to pure PEO and PEO/clay nanocomposites. 相似文献
112.
İzzet Yilmaz Önel Engin Ayçiçek İbrahim Şenol 《Journal of Intelligent Manufacturing》2009,20(2):243-247
This paper describes an application about detection of bearing defects in inverter fed induction motors, using Concordia transform
approach based algorithm. After introduction, brief information is given about bearing structure and type of bearing failures.
Next section, Concordia transform theory is mentioned then, RBF neural network structure is summarized. After that, test system
information is specified. This paper indicates that Concordia transform approach is a reliable tool to detect bearing faults
in inverter fed small induction motors. The generality of the proposed methodology has been experimentally tested on a 1 HP
squirrel-cage induction motor. At the end of the paper, an ANN algorithm is proposed that could detect the bearing faults
automatically. The obtained results have 93.75% accuracy. This study suggests that proposed Concordia transform based fault
detection algorithm could be integrated in an induction motor driver so, bearing condition of the induction motor could be
observed while motor is working and bearing faults could be detect before they become serious. 相似文献
113.
瓦楞辊有限元模态分析 总被引:3,自引:0,他引:3
采用有限元方法,建立了瓦楞辊的有限元动力学模型,用ANSYS5.7软件研究了瓦楞辊的固有特性。所得结果既反映了瓦楞辊的动力学性能,又为瓦楞辊的动态响应计算和分析奠定了基础. 相似文献
114.
An approximation was applied to a solar cell equation to eliminate reverse saturation current. I–U curves obtained from the approximated equation were fitted to experimentally measured data by using the iteration technique. All instrumentation errors were taken into account in the fitting procedure. The Filling Factor (FF) and the series resistance (Rs) appeared to be important for fitting accuracy. The fitting procedure was repeated for different illuminations and solar cell temperatures. 相似文献
115.
This work extends the applicability of variable structure observers designed for nonlinear systems in two ways. First, it is proved that these observers using a boundary-layer scheme can be applied to system models described by Ito differential equations, resulting in almost sure and mean square exponential estimation error. Second, the use of variable structure observers is extended to nonlinear measurement models containing disturbance effects. Also, a novel approach for obtaining the required parameters in the observer design is provided. Finally, two examples are given to illustrate the application and favorable convergence properties of these generalizations. 相似文献
116.
A novel circulating jet loop bioreactor adapted for organic matter oxidation has been designed and constructed. In this study, the input was leachate samples collected from Kemerburgaz Odayeri waste landfill site located on the European side of Istanbul. Controlling the jet loop bioreactor to realize high rates of purification depends on maintaining the appropriate loadings and operating conditions. This requires collecting various system data to estimate the dynamics of the system satisfactorily with the aim of keeping certain parameters within the specified range. The differential transform method (DTM) based solution of the state equations reveals the current state of the process so that any deviation in the system parameters can be immediately detected and regulated accordingly. The respirometric method for kinetic parameter calculations for biodegradation has been used for some time. In many studies, the respirometer was designed separately, usually in bench-scale. However, when a separate respirometer is used, the scale effect and parameters that affect the hydrodynamic structure of the system should be taken into consideration. In this study, therefore, the jet loop reactor itself was used as a respirometer. Thus, the kinetic parameters found reflecting the characteristics of microorganisms used for biodegradation would be more realistic. If the main reactor, here the jet loop reactor, would be used as the respirometer, the kinetic parameter changes can easily be monitored in the long run. Using the bioreactor as a respirometer, the most important kinetic parameters, Ks, kd and micromax were found to be 11,000 mg L(-1), 0.019 day(-1), and 0.21 day(-1), respectively. The stoichiometric coefficient, Y, was found to be 0.28 gr gr(-1) for the present system. 相似文献
117.
The residential vegetation features in urban landscapes play an important role as indicators regarding urban biodiversity potential and cultural changing. They also include ornamental resources in the context to landscape appreciation for human environment. Therefore, this paper provides quantitative information on the distribution of plant species in urban residential landscape areas of Trabzon city (Turkey). In a total of 218 sampled areas, 274 plants species belonging to 70 families were surveyed with respect to residential use types of the city. The study results showed that among the species recorded in five residential type (traditional housing, detached housing, villa, apartment blocks and sites, mass housing for employees), non-native taxa frequency of a total species are much and dominantly represent residential landscape structure. Additionally, the species richness and diversity is positively related to new urban development areas. But, it was clearly determined that the vegetation structure has tended to ornamental purposes different from traditional residential gardens including fruit and other benefiting species. Consequently, it can be evidence that the residential vegetation is ornamental plant resources to urban biodiversity and that the distribution of the species in urban landscapes follows necessities of city and human quality. 相似文献
118.
Engin Arslan Mustafa K. Ozturk Huseyin Çakmak Pakize Demirel Süleyman Özçelik Ekmel Ozbay 《Journal of Materials Science: Materials in Electronics》2013,24(11):4471-4481
The InxGa1?xN epitaxial layers, with indium (x) concentration changes between 0.16 and 1.00 (InN), were grown on GaN template/(0001) Al2O3 substrate by metal organic chemical vapour deposition. The indium content (x), lattice parameters and strain values in the InGaN layers were calculated from the reciprocal lattice mapping around symmetric (0002) and asymmetric (10–15) reflection of the GaN and InGaN layers. The characteristics of mosaic structures, such as lateral and vertical coherence lengths, tilt and twist angle and heterogeneous strain and dislocation densities (edge and screw dislocations) of the InGaN epilayers and GaN template layers were investigated by using high-resolution X-ray diffraction (HR-XRD) measurements. With a combination of Williamson–Hall (W-H) measurements and the fitting of twist angles, it was found that the indium content in the InGaN epilayers did not strongly effect the mosaic structures’ parameters, lateral and vertical coherence lengths, tilt and twist angle, or heterogeneous strain of the InGaN epilayers. 相似文献
119.
In this study, novel conductive fabrics were developed by polymerising of aniline onto the polyamide (PA)-knitted fabrics. The fabric treatment was done by the chemical polymerisation method at 0.5, 0.8 and 1.2?M aniline concentrations. Hydrochloric acid as acidic medium and ammonium per sulphate as oxidant were employed during the polymerisation process. The polyaniline (PANI)-treated PA fabric structures were fully characterised and evaluated in terms of their electromagnetic shielding effectiveness, absorption and reflection characteristics and tensile properties. Additionally, the fabrics were examined by scanning electron microscope (SEM) for the surface morphology and Fourier transform infrared spectroscopy for the chemical functionality. The electromagnetic shielding effectiveness, absorption and reflection characteristics were determined by Network Analyzer with a frequency ranged from 15 to 3000 MHz. The electrical characteristics were measured by the two ends method. It has been concluded that the bursting strength values of the treated fabrics reduced when the amount of monomer in the concentrations decreased as compared to the untreated fabrics. It is interesting to note that 1.2 M treated fabric had the highest bursting strength values as compared to the other treated fabrics. It was also found that 0.5 M concentration of PANI-treated fabric had the lowest surface resistivity due to this it showed the highest conductivity value. Another important finding is that the 0.5 M-aniline treated fabric had the highest shielding effectiveness. 相似文献
120.
Torsion of structural members and the behavior of steel fiber reinforced concrete became the area of interest of many researchers in the past and it is still newsworthy. In this study, 12 reinforced concrete (R/C) beams with Steel Fiber Reinforced Concrete (SFRC) were tested to observe the failure under torsional moments. The volumetric steel fiber content, fiber aspect ratio, and the longitudinal reinforcement were the variables of the investigation. Unit torsional angle of twist versus torsional moment (torque) response of each specimen was monitored during the experiments, and the effect of above variables on this response was critically investigated. It was observed that not only the torque capacity of R/C beam is modified by the addition of Steel Fiber Reinforcement (SFR) but also the energy absorption capacity is significantly affected by the SFR addition. Besides, an empirical equation relating the torque to twist for SFRC beams is proposed and tested against the test data. 相似文献