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1.
Deactivation of copper-ion-exchanged hydrogen-mordenite-type zeolite catalyst by SO2 for NO reduction by NH3 was examined in a fixed-bed flow reactor. The deactivation of the catalyst was strongly dependent on reaction temperature. At high reaction temperatures over 300°C, the catalyst did not lose its initial activity up to 50 h of operation, regardless of SO2 feed concentration from 500 to 20,000 ppm. However, at low reaction temperatures near 250°C, apparent deactivation did occur. Changes in the physicochemical properties such as surface area and sulfur content of deactivated catalyst well correlated with catalyst activity, depending upon reaction temperatures. The deactivation was due to pore blocking and/or filling by deactivating agents, which plugged and/or filled the pores of catalyst. The deactivating agents deposited on the catalyst surface were presumed to be (NH4)2SO4 and/or (NH4)HSO4 from the results of TGA and ion-chromatography measurement. 相似文献
2.
Database considerations in manufacturing systems integration 总被引:1,自引:0,他引:1
This paper deals with ideas that could form a basis for manufacturing integration. In recent times more attention is being paid to the idea of applying artificial intelligence (AI) techniques to manufacturing. However, very little attention is being paid to the proper use of these techniques. This research work explores three basic ideas:
1. 1. Applications of the entity-relationship approach to knowledge representation.
2. 2. The basic philosophy of expert database systems and
3. 3. Integration of manufacturing systems from the above two concepts.
The approaches for 1 and 2 are explained with actual implementation experiences, while a framework for integration is proposed from a more philosophical perspective. 相似文献
3.
Woonchul Ham 《Automatic Control, IEEE Transactions on》1993,38(4):654-658
Adaptive and nonadaptive control algorithms, which make use of a fundamental mathematical property concerning positive definite matrices and Lyapunov stability theory, are proposed for the control of robot manipulators. Using the fact that the matrix dD (q )/dt -2C (q , dq / dt ) is skew symmetric, nonadaptive controllers which have a simplified structure with less computational burden are proposed. Using the dynamic equations for robot manipulators, parameter adaptation rules are developed for updating the controller's partially or totally unknown parameters, generalizing them to model reference adaptive controllers. To further take advantage of the simplified structure of the proposed adaptive controllers, a method for deriving the dynamic model of a robot manipulator which is linear in terms of its parameters is given. This dynamic model is also suitable for the pure identification of the parameters of links and payload of the manipulator 相似文献
4.
Kyungmin Ham 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,262(1):117-127
The conversion of X-ray tomography images into three-dimensional chemical composition requires accurate mass absorption values, high-quality images, and a robust fitting algorithm. The least-squares fits of the images to a three-dimensional chemical composition can proceed with several different options such as minimal vs. over-determined and/or constrained parameters. This project has investigated the impact of XAFS features and a limited CCD dynamic range. These simulated results are compared to a recent experimental project in which synchrotron X-ray tomography was used to image a polymer blend, and from those images, calculated three-dimensional chemical composition maps of the two-component flame retardant, a brominated phthalimide dimer, Saytex™ BT-93 and a synergist, antimony(III) oxide (Sb2O3). 相似文献
5.
Uncertainty in water quality model predictions is inevitably high due to natural stochasticity, model uncertainty, and parameter uncertainty. An integrated modelling system (modified-BASINS) under uncertainty is described and demonstrated for use in receiving-water quality prediction and watershed management. A Monte Carlo simulation was used to investigate the effect of various uncertainty types on output prediction. Without pollution control measures in the watershed, the concentrations of total nitrogen (T-N) and total phosphorus (T-P) in the Hwaong Reservoir, considering three uncertainty types, would be less than about 4.4 and 0.23 mg L(-1), respectively, in 2012, with 90% confidence. The effects of two watershed management practices, wastewater treatment plants (WWTP) and constructed wetlands (WETLAND), were evaluated. The combined scenario (WWTP + WETLAND) was the most effective at improving reservoir water quality, bringing concentrations of T-N and T-P in the Hwaong Reservoir to less than 3.4 and 0.14 mg L(-1), 24 and 41% improvements, respectively, with 90% confidence. Overall, the Monte Carlo simulation in the integrated modelling system was practical for estimating uncertainty and reliable in water quality prediction. The approach described here may allow decisions to be made based on the probability and level of risk, and its application is recommended. 相似文献
6.
Ju Ri Ham Ra-Yeong Choi Yongjin Lee Mi-Kyung Lee 《International journal of molecular sciences》2021,22(7)
Mealworms (Tenebrio molitor larva) are an edible insect and a protein-rich food; however, research on mealworms as a substitute protein is insufficient. In this study, mealworm fermentation extract (TMP) was assessed as a replacement for soy protein (SP) in a control diet (CON) or a high-fat diet (HFD) of mice for 12 weeks. TMP substitution reduced body weight, body weight gain, body fat mass (perirenal and mesenteric), fat size, glucose intolerance, and insulin resistance compared to the HFD-SP group. TMP alleviated hepatic steatosis (lipid contents and lipid droplets) in high-fat-fed mice and down-regulated the PPARγ, CD36, and DGAT2 gene levels. Proteomic analysis showed that a HFD for 12 weeks up-regulated 20 proteins and down-regulated 17 proteins in mice fed SP. On the other hand, TMP reversed the protein profiles. TMP significantly down-regulated KHK, GLO1, ATP5H, SOD, and DDAH1 and up-regulated DLD, Mup1, CPS1, Ces3b, PDI, and HYOU1 compared to the HFD-SP group. These proteins are involved in the glucose, lipid, and amino acid metabolism, as well as in oxidative stress and endoplasmic reticulum stress. Thus, substituting SP for TMP helped improve HFD-induced obesity, steatosis, and insulin resistance in mice. These results suggest that TMP is a potential substitute for commonly used protein sources. 相似文献
7.
A 5 wt% CoOx/TiO2 catalyst has been used to study the effect of calcination temperature on the activity of this catalyst for CO oxidation at 100 °C under a net oxidizing condition in a continuous flow type fixed-bed reactor system, and the catalyst samples have been characterized using TPD, XPS and XRD measurements. The catalyst after calcination at 450 °C gave highest activity for this low-temperature CO oxidation, and XPS measurements yielded that a 780.2-eV Co 2p3/2 main peak appeared with this catalyst sample and this binding energy was similar to that measured with pure Co3O4. After calcination at 570 °C, the catalyst, which had possessed practically no activity in the oxidation reaction, gave a Co 2p3/2 main structure peak at 781.3 eV which was very similar to those obtained for synthesized ConTiOn+2 compounds (CoTiO3 and Co2TiO4), and this catalyst sample had relatively negligible CO chemisorption as observed by TPD spectra. XRD peaks indicating only the formation of Co3O4 particles on titania surface were developed in the catalyst samples after calcination at temperatures ≥350 °C. Based on these characterization results, five types of Co species could be modeled to exist with the catalyst calcined at different temperatures. Among these surface Co species, the Type A clean Co3O4 particles were predominant on a sample of the catalyst after calcination at 450 °C and highly active for CO oxidation at 100 °C, and the calcination at 570 °C gave the Type B Co3O4 particles with complete ConTiOn+2 overlayers inactive for this oxidation reaction. 相似文献
8.
Polyvinylpyrrolidone (PVP)/sodium montmorillonite (MMT) nanocomposites prepared via the solution intercalation method were investigated by UV/vis, SEM, X-ray diffraction, TEM, FT-IR and PLM (polarized light microscopy). PVP/MMT nanocomposites show exfoliation below 20 wt% MMT and intercalation above this concentration. Nanocomposites retain good optical clarity and increased thermal resistance with MMT content. The compatibility between PVP and MMT and their enhanced properties may be explained by hydrogen bonding interactions. In addition, the nanocomposites prepared under more rigorous mixing conditions show better transparency because the smaller particle sizes are induced. In addition, the study on optically clear PVP/MMT suspensions helps one to understand how optical anisotropy of MMT is affected by the existence of polymer in aqueous solution. 相似文献
9.
Soo?Tae?Choo In-Sik?NamEmail author Sung-Won?Ham Jeong-Bin?Lee 《Korean Journal of Chemical Engineering》2003,20(2):273-278
The catalytic activity of sulfated titania (ST) calcined at a variety of temperatures has been investigated for selective catalytic reduction (SCR) of NO by NH3. The NO removal activity of ST catalyst mainly depends on its sulfur content, indicating critical role of sulfur species on the surface of TiO2. The role of sulfur is mainly the formation of acid sites on the catalyst surface. The presence of both BrØnsted and Lewis acid sites on the surface of sulfated titania has been identified by IR study with the adsorption of NH3 and pyridine on ST. The reduction of the intensity of IR bands representing BrØsted acid sites is more pronounced than that revealing Lewis acid sites as the calcination temperature increases. It has been further clarified by IR study of ST500 catalyst evacuated at a variety of temperatures. The NO removal activity also decreases with the increase of the catalyst calcination temperature. It simply reveals that BrØnsted acid sites induced by sulfate on the catalyst surface are primarily responsible for the enhancement of catalytic activity of ST catalyst containing sulfur for NO reduction by NH3. 相似文献
10.
Single Point Incremental Forming (SPIF) is a modern method of forming sheet metal, where parts can be formed without the use of dedicated dies. The ability of SPIF to form a part is based on various forming parameters. Previous work was not accomplished with the help of design of experiments, thus reducing the number of parameters varied at any time. This paper presents two designs of experiments, which formalise the forming parameters critical in SPIF and the degree to which they affect formability. 相似文献