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131.
132.
Tung Bui Sungwon Cho Siva Sankaran Michael Sovereign 《Information Systems Frontiers》2000,1(4):427-442
Large-scale Humanitarian Assistance/Disaster Relief (HA/DR) operations, particularly in developing countries, require the intervention and aid of various agencies from all over the world in a concerted and timely manner. As a result, HA/DR operations involve dynamic information exchange, planning, coordination and above all negotiation. Although a number of studies have reported the benefits of using information and communication technologies to support negotiation activities, it remains unclear how such technologies could be adapted to large-scale HA/DR operations. This paper examines negotiational issues involved in a multinational HA/DR environment and presents a framework that would help in developing a Global Information Network (GIN). The proposed framework can be used to assess and characterize individual disaster situations so that the GIN functional and design requirements can be accurately identified early. Future implications to GIN architecture are also discussed. 相似文献
133.
We developed a scientific proposal on spectral absorption in remote sensing and a new image-processing method that is purely based on multispectral satellite image spectra to map ultramafic lamprophyre and carbonatite occurrences. The proposed method provides a simple, yet efficient, tool that will help exploration geologists. In this proposal, in which the spectral absorption is applicable to all satellite images obtained in visible, reflected infrared, and thermal infrared spectral wavelength regions, we found that the carbonatites appear white in colour on a greyscale or RGB thermal infrared image obtained in the thermal infrared wavelength region (3–15 μm) due to molecular emission of thermal energy by such carbonate content, particularly the wavelength recorded by the sensor and that the variation of absorption in spectral bands of an outcrop is due to the differences in percentage of carbonate content or the spectral, spatial, radiometric, or temporal resolution of satellite data or the occurrences of carbonatites to incident energy. The results were confirmed by studying the spectral absorption characteristics of carbonatites in selected world occurrences including parts of Batain Nappe, Oman; Fuerteventura (Canary Islands), Spain; Mount Homa, Kenya; Ol Doinyo Lengai, Tanzania; Mount Weld region, (Laverton), Australia, and Phalaborwa region, South Africa, using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) satellite data. A subsequent study of visible near-infrared (VNIR) and shortwave infrared (SWIR) ASTER spectral bands of Early Cretaceous alkaline ultramafic rocks of Batain Nappe, along the northeastern margin of Oman to map for the occurrences of carbonatite and aillikite (ultramafic lamprophyres) dikes and plugs, showed their detection mainly by the diagnostic CO3 absorption (2.31–2.33 μm) in ASTER SWIR band 8. The results of image interpretations were verified and confirmed in the field and were validated through the study of laboratory analyses. A few more carbonatite dike occurrences were interpreted directly over the greyscale image of ASTER bands and true-colour interpretations of a Google Earth image along this margin. The carbonatites and aillikite occurrences of the area are rich in apatite, iron oxide, phlogopite, and REE-rich minerals and warrant new exploration projects. 相似文献
134.
Pneumatic conveying of granular solids in vertical and inclined risers was studied using electrical capacitance tomography (ECT). The focus of the study was on flow development past a smooth bend connecting the riser to a horizontal duct which brought the gas-particle mixture to the riser. In the vertical riser, dispersed flow manifested a core-annular structure, whose development is discussed. Three different time-dependent flow patterns were imaged. Slugging flow, which appeared to be intrinsic to riser flow, took the form of alternating bands of core-annular disperse flow and a slug with a particle-rich core. Averaging over these two structures yielded a composite distribution with high particle concentration both at the axis and the wall region. Pulsing flow, whose ECT fingerprint was similar to that of slugging flow, was largely an entrance effect. Stationary and moving annular capsules with a dilute core were also observed, and such flow patterns do not appear to have been reported previously. Our ECT measurements probing the development of disperse flow in an inclined riser past a bend revealed that the particle loading initially decreased, subsequently increased and then leveled off. Regimes such as eroding dune flow and flow over a settled layer could be easily imaged using ECT. The surface of the settled layer had a concave shape, suggesting that the particles were picked up from the settled layer by airflow at the center and deposited on the sides of the tube. 相似文献
135.
Diglycidyl ether–bisphenol-A-based epoxies toughened with various levels (0–12%) of chemically reacted liquid rubber, hydroxyl-terminated poly(butadiene-co-acrylonitrile) (HTBN) were studied for some of the mechanical and thermal properties. Although the ultimate tensile strength showed a continuous decrease with increasing rubber content, the toughness as measured by the area under the stress-vs.-strain curve and flexural strength reach a maximum around an optimum rubber concentration of 3% before decreasing. Tensile modulus was found to increase for concentrations below 6%. The glass transition temperature Tg as measured by DTA showed no variation for the toughened formulations. The TGA showed no variations in the pattern of decomposition. The weight losses for the toughened epoxies at elevated temperatures compare well with that of the neat epoxy. Scanning electron microscopy revealed the presence of a dual phase morphology with the spherical rubber particles precipitating out in the cured resin with diameter varying between 0.33 and 6.3 μm. In contrast, a physically blended rubber–epoxy showed much less effect towards toughening with the precipitated rubber particles of much bigger diameter (0.6–21.3 μm). 相似文献
136.
This paper deals with design and simulation of a three-phase shunt hybrid power filter consisting of a pair of 5th and 7th selective harmonic elimination passive power filters connected in series with a conventional active power filter with reduced kVA rating. The objective is to enhance the power quality in a distribution network feeding variety of non-linear, time-varying and unbalanced loads. The theory and modelling of the entire power circuit in terms of synchronously rotating reference frame and leading to a non-linear control scheme is presented. This work involves introduction of individual fuzzy logic controllers for d and q axis current control and for voltage regulation of the DC link capacitor. The simulation schematic covering the power and control circuits have been developed taking into account severe harmonic distortion caused by non-linear and unbalanced loads. The effectiveness of the fuzzy logic controller for the compensation of harmonics and reactive power has been verified by successive simulation runs and analysis of the results. The proposed controller is also able to compensate the distortion generated by the voltage- and current-fed non-linear loads, unbalanced and dynamically varying loads. Further, excellent regulation of the DC link voltage is accomplished, which significantly contributes to improvement of power quality. 相似文献
137.
A Taguchi Design of Experiment Approach to Pulse and Lock in Thermography,Applied to CFRP Composites
Y. A. Abdulrahman M. A. Omar Z. Said F. Obeideli A. Abusafieh G. N. Sankaran 《Journal of Nondestructive Evaluation》2017,36(4):72
The current text presents a parametric study of two active thermography routines namely, Pulse and Lock-in as applied to carbon fiber reinforced plastics (CFRP) composites; using a Taguchi design of experiment approach. A set of controllable factors are highlighted and selected for each technique at different levels. Three factors have been identified for the pulse thermography (specifically; defect aspect ratio, pulse period, and experimental duration), and two factors for the Lock-in mode (that is lock in frequency and period); each factor can be manipulated at three different levels. The analysis reveals the effectiveness of the Taguchi design of experiment in consolidating the number of factorial experiments, and in quantifying the results and the associated sensitivity for each factor (its dominance), using a signal to noise ratio criterion. The analysis of variance and analysis of means show that the aspect ratio is not a controlling parameter for the pulse thermography, with the pulse time being the most dominant. Moreover, it decides on the optimal settings for each testing mode. These settings are further validated using additional CFRP artificial sample with eight and six layers of laminates. 相似文献
138.
Revathy Sankaran Pau Loke Show Yee Jiun Yap Yang Tao Tau Chuan Ling Katsuda Tomohisa 《Clean Technologies and Environmental Policy》2018,20(9):2001-2012
Liquid biphasic flotation (LBF) system has been recognized as an efficient, green, economically sustainable and biocompatible technique for biomolecules separation and purification. The main drawbacks of the conventional process of biomolecules separation are expensive production cost, utilization of phase components that are inefficiently recycled and global pollution due to high chemical consumption and wastage. In this paper, a novel approach of LBF system for lipase recovery utilizing recycling phase components comprising surfactant and xylitol was investigated. The scope of this study focuses on pollution prevention as well as clean and environmentally friendly process for enzyme extraction via LBF. The green process proposed in this study uses phase-forming components that have recovery and recycling abilities for minimal use of chemicals for enzyme extraction. This novel method utilized Triton X-100 and xylitol for lipase extraction from Burkholderia cepacia. A few parameters were optimized to obtain high lipase separation efficiency and yield. Based on the ideal conditions of LBF, the average lipase separation efficiency and yield are 86.46 and 87.49%, correspondingly. Phase components recycling were proposed in order to reduce the chemicals consumption in LBF system. Upscaling of the recycling study exhibited consistent result with the laboratory scale. It was found that 97.20 and 98.67% of Triton X-100 and xylitol were recovered after five times of recycling and that a total of 75.87% of lipase separation efficiency was obtained. Recovery and recycling of phase components in the extraction process are established as the principal green chemistry method, which yields high separation efficiency and is economically feasible on an industrial scale. 相似文献
139.
Structural and Multidisciplinary Optimization - This paper proposes formulations and algorithms for reliability-based design optimization (RBDO) of both single and multidisciplinary systems under... 相似文献
140.
John McFarland Sankaran Mahadevan 《Computer Methods in Applied Mechanics and Engineering》2008,197(29-32):2467
The importance of modeling and simulation in the scientific community has drawn interest towards methods for assessing the accuracy and uncertainty associated with such models. This paper addresses the validation and calibration of computer simulations using the thermal challenge problem developed at Sandia National Laboratories for illustration. The objectives of the challenge problem are to use hypothetical experimental data to validate a given model, and then to use the model to make predictions in an untested domain. With regards to assessing the accuracy of the given model (validation), we illustrate the use of Hotelling’s T2 statistic for multivariate significance testing, with emphasis on the formulation and interpretation of such an analysis for validation assessment. In order to use the model for prediction, we next employ the Bayesian calibration method introduced by Kennedy and O’Hagan. Towards this end, we discuss how inherent variability can be reconciled with “lack-of-knowledge” and other uncertainties, and we illustrate a procedure that allows probability distribution characterization uncertainty to be included in the overall uncertainty analysis of the Bayesian calibration process. 相似文献