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41.
Mustafa Öğütcü Buket Aydeniz Mehmet Burak Büyükcan Emin Yılmaz 《Journal of the American Oil Chemists' Society》2012,89(10):1823-1830
A rapid method for the determination of some important physicochemical properties in frying oils has been developed. Partial least square regression (PLS) calibration models were applied to the physicochemical parameters and near infrared spectroscopy (NIR) spectral data. PLS regression was used to find the NIR region and the data pre-processing method that give the best prediction of the chemical parameters. Calibration and validation were appropriated by leave one out cross validation and test set validation techniques for predicting free fatty acids (FFA), total polar materials (cTPM; measured by chromatographic method and iTPM measured by an instrumental method), viscosity and smoke point of the frying oil samples. For PLS models using the cross validation techniques, the best correlations (r) between NIR predicted data and the standard method data for iTPM in oils were 93.79 and root mean square error of prediction (RMSEP) values were 5.53. For PLS models using the test set validation techniques, the best correlations (r) between NIR predicted data and standard method data for FFA, cTPM, viscosity and smoke point in oils were 92.58, 94.61, 81.95 and 84.07 and RMSEP values were 0.121, 3.96, 22.30 and 8.74, respectively. In conclusion, NIR technique with chemometric analysis was found very effective in predicting frying oil quality changes. 相似文献
42.
The interaction between soil and structure plays a crucial role on accurate determination of structures' seismic behavior. The assumption of fixed base structure has been commonly used in traditional design works, and the interaction between soil and structure is thus often neglected. In addition, historical masonry structures particularly built on elastic soil media may be significantly affected seismic behavior of the structure under earthquakes. In this research, the damage distribution on a historical masonry minaret is numerically investigated under horizontal earthquake ground motion. Alaca Mosque minaret was built in 1271 in Bolvadin district of Afyon province. The historical masonry minaret was chosen as the subject of the study. Nonlinear seismic time history analyses were conducted for fixed‐based and different soil properties under horizontal earthquake ground motion. The horizontal (East–West) component acceleration records of Dinar earthquake (Mw = 6.1) that took place on October 10, 1995, were used during the analyses. Maximum displacement, maximum/minimum principal stresses, and damage ratios were determined by nonlinear analyses performed considering fixed base and soil–structure interaction. The analysis results showed that soil–structure interaction had significant effect on the structural behavior of the minaret, such that, the minaret that was expected to get damage in the case of fixed base did not get any damage when soil–structure interaction was considered. 相似文献
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44.
The purpose of this research was to develop olive oil organogels with sunflower wax (SW) and beeswax (BW) at 3%, 7%, and 10% addition levels and to compare these organogels with breakfast margarine (BM). The organogels and BM sample were stored at 2 different temperatures (4 and 20 °C), and the peroxide values (PVs) and textural properties were monitored for 3 mo. The PVs of all organogels were within legal limits and the gels were structurally stable throughout the storage period. The textural properties of 3% SW and 7% BW organogels were closely similar to BM. The solid fat contents of the organogels were lower than that of the BM. Moreover, the thermal properties of 3% BW gel were more similar to that of the BM. The results of X‐ray diffraction peaks, approximately 3.70 and 4.10 Å, were similar to β′ polymorphic form. In conclusion, both of the organogel types may have value in replacing BMs. 相似文献
45.
Emin C. Dogrul Tariq N. Kadir Francis I. Chung 《Canadian Metallurgical Quarterly》2011,137(6):359-366
An important issue that integrated hydrologic models (IHMs) for river basins can address is the management of water resources in heavily inhabited and cultivated basins. To address this issue, these models need to simulate water demands and root zone flows in a basin. Irrigation scheduling models (ISMs) have been widely used by professionals to compute farm level water demands and root zone flows. Available ISMs are neither suitable for use at basin scale nor can they be easily linked to IHMs. This paper describes a new model that utilizes methods used by ISMs to compute root zone flows and water demands in river basins and can be linked to IHMs. The model was applied to a basin in California, and the simulated water demands were compared with data compiled for the basin. The differences in the results were attributed to differences in input potential evapotranspiration rates. The paper demonstrates that simulated water demands for rice are very sensitive to saturated soil hydraulic conductivity, whereas demands for other crops are sensitive to the pore size distribution index. 相似文献
46.
RFID technology continues to flourish as an inherent part of virtually every ubiquitous environment. However, it became clear
that the public—implying the industry—seriously needs mechanisms emerging the security and privacy issues for increasing RFID
applications. As the nodes of RFID systems mostly suffer from low computational power and small memory size, various attempts
which propose to implement the existing security primitives and protocols, have ignored the realm of the cost limitations
and failed. In this study, two recently proposed protocols—SSM and LRMAP—claiming to meet the standard privacy and security
requirements are analyzed. The design of both protocols based on defining states where the server authenticates the tag in
constant time in a more frequent normal state and needs a linear search in a rare abnormal states. Although both protocols
claim to provide untraceability criteria in their design objectives, we outline a generic attack that both protocols failed
to fulfill this claim. Moreover, we showed that the SSM protocol is vulnerable to a desynchronization attack which prevents
a server from authenticating a legitimate tag. Resultantly, we conclude that defining computationally unbalanced tag states
yields to a security/scalability conflict for RFID authentication protocols. 相似文献
47.
Mehmet Emin Yuksekkay 《Textile Progress》2013,45(3):141-193
Unfortunately, the classical empirical friction laws do not hold true for fibrous and viscoelastic materials comprising most of the textile fibres. In the second half of the twentieth century, fibre surfaces have been studied by many distinguished scientists who were able to complete numerous researches for the frictional characteristics of different types of fibres. Most of the researchers have aimed to develop a new test method and a test device that can be used to measure the frictional characteristics of fibres quickly, accurately and easily in their studies. Unfortunately, there is not a standard test method or a test device for the measurement of textile fibres' friction properties. For today's competitive marketing, the instrument for fibre testing must be very fast and accurate; otherwise, it will not be useful for commercial purposes. For example, hundreds of thousands of cotton bales should be tested within a very short period of time in terms of the length, colour and trash content of the cotton bales. Without having the data describing the properties of cotton fibres, cotton bales cannot be sold commercially in most of the countries. Therefore, it is an important factor that the fibre-testing instrument should be fast and accurate. Most of the properties of cotton fibres can be assessed by using a HVI fibre-testing instrument. In this review, the historical perspective of fibre friction studies has been demonstrated with the fibre friction measurement-testing devices. 相似文献
48.
Formation of oil droplets during twin screw extrusion processing of maize starch was investigated by analyzing the droplet breakup and coalescence mechanisms separately. For this purpose, the flow was characterized by computational fluid dynamics (CFD) using material data derived from online rheological measurements. The simulated results on local flow conditions were coupled to experimental data on the dispersed phase morphology, which was analyzed by confocal laser scanning microscopy (CLSM). This was used to elucidate the influence of process characteristics relevant for droplet breakup and coalescence. The results showed that increasing screw speed does not necessarily result in smaller droplet sizes. This could be related to the contradictory effects: increasing screw speed improves droplet breakup but also increases the rate of coalescence. Smaller droplet sizes were obtained at higher blend viscosities, which could be achieved either by increasing the feed rate or by using screw configuration that applies less mechanical stress. The results suggest that an increase in blend viscosity reduced the rate of coalescence. Moreover, increasing oil content led to an increased rate of coalescence, and therefore to remarkably bigger droplets. Selection of process parameters (e.g. screw configuration, feed rate, screw speed) based on the findings of this study allowed enhancing the dispersive mixing efficiency of triglyceride droplets during extrusion processing of maize starch. 相似文献
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50.
Hakan Murat Karaca Tolga Kurt Salih Zafer Dicle Emin Anarim 《Wireless Personal Communications》2013,72(2):1259-1275
Cognitive radio is an emerging technique to improve the utilization of radio frequency spectrum in wireless communication networks. That is, spectrum efficiency can be increased significantly by giving opportunistic access of the frequency bands to a group of cognitive users to whom the band has not been licensed. In this paper, as a cross layer application (MAC and physical layers) of graph theory, we consider the problem of throughput maximization of spectrum allocation in cognitive radio networks under interference constraint. We propose a novel auction-based channel allocation mechanism which tries to maximize both total and primary users’ utilities while satisfying signal to interference ratio constraint on primary receivers so that transmitted packets will be successfully received, without controlling secondary user powers. For comparison we discuss a greedy algorithm as well, however, one that does not handle interference issue. In order to compare results of proposed and greedy algorithms, we propose net throughput by taking into account outage probability of primary receiver. Simulation results show that exposing higher SINR (outage) threshold not only decreases total gain and primary users’ utilities but also worsens channel distribution performance. On the other hand adding auction mechanism significantly increases total gain throughput and primary user’ s utility. Particularly, up to SINR threshold values of 20 dBs, auction provides outstanding performance and proposed algorithm has total throughput results close to those of the greedy one even though no interference constraint is applied in the greedy algorithm. Another noticeable point of simulation results is crossover of net throughputs of proposed and greedy algorithms at a SINR threshold level after which results of ABSA-UNIC and NASA-UNIC are much better. This clearly shows superiority of proposed mechanism. 相似文献