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71.
Detlef Ahrens 《European Journal of Lipid Science and Technology》1999,101(7):230-234
Development of thin-film deodorizers started in the 1970ies, and they have been in industrial use since the middle of the 1980ies. The latest type is the SoftColumnTM, a deodorizer specially developed for mild, low cost processing of seed oils. This deodorizer consists of a structured packing section and a flexible holding section. Regenerative oil heating/cooling and final heating is carried out in external, sparged vacuum heat exchangers, and the design of the heat exchangers leads to superior heat recovery and savings in fuel consumption. This set-up provides major advantages with regard to oil quality, economy, and flexibility. The extremely effective stripping of free fatty acids (FFAs) leads to shorter overall holding times of the oil at elevated temperatures, and steam consumption is cut to a third of the amount required in conventional deodorizers. The product oil has not only low acidity, low colour, good taste and stability, but also low trans fatty acid (TFA) concentrations. By adjusting the stripping steam flow the plant can be optimized both for tocopherol retention or removal. Flexible holding times allow optimization of heat bleaching/TFA formation without compromising on capacity. In this paper product analysis data on tocopherol and trans fatty acids from thin-film deodorizers in industrial operation are shown. 相似文献
72.
Hydrothermal Treatment of Starch in Presence of α-Amylase. Part 3: Changes of Rheological Properties of Wheat Starch by Hydrothermal Enzymatic Treatment . In order to change functional properties of wheat starch the feasibility for a hydrothermal enzymatic modification under conditions of excess water (annealing) has been tested. The granular structure of the starch should remain unchanged at the same time. Since wheat starch may be changed negligiblely at usual conditions of annealing (T=50°C) as a consequence of its rather low swelling temperature a bacterial α-amylase has been used for partial degradation of these portions of starch granules which gelatinize irreversiblely at higher levels of annealing temperatures. The resulting spectrum of saccharides consisting mainly of maltose (approx. 50%) allows the protection of the wheat starch matrix even at higher annealing temperatures (54°C). However, the gelatinization and gelation behaviour is changed in a characteristic way, in particular by a serious increase of the hot paste consistency at 95°C. In the following, the obtained consistency collapses significantly and arrives by cooling a level below the corresponding figures of the native starch. With respect to yield of annealed starch the reaction time at elevated temperature is of main importance. In order to demonstrate the protecting activity of the produced saccharides in particular with higher concentrations of maltose samples have been annealed in maltose sirups of varied concentration (6, 12, 25%m/m). Up to concentrations of 12%m/m and reaction temperatures of 50°C the Brabender consistency curves could be raised by 300 to 500BU. The application of 54°C limited the effect of modification. Using a 25%m/m maltose syrup allowed, of course, successfully the annealing at 54°C. As expected, yield losses remained low (< 10%). In applying a temperature-time-regime by steps together with a treatment by α-Amylase or alternatively 25%m/m maltose syrup the expected shifting of consistency curves could be observed as well, however, to a limited amount. Finally, pronounced differences could be found for the yield of modified starches. 相似文献
73.
Spectral particle extinction coefficients of atmospheric aerosols were measured with, to the best of our knowledge, a newly designed differential optical absorption spectroscopy (DOAS) instrument. A closure study was carried out on the basis of optical and microphysical aerosol properties obtained from nephelometer, particle soot/absorption photometer, hygroscopic tandem differential mobility analyzer, twin differential mobility particle sizer, aerodynamic particle sizer, and Berner impactors. The data were collected at the urban site of Leipzig during a period of 10 days in March 2000. The performance test also includes a comparison of the optical properties measured with DOAS to particle optical properties calculated with a Mie-scattering code. The computations take into account dry and ambient particle conditions. Under dry particle conditions the linear regression and the correlation coefficient for particle extinction are 0.95 and 0.90, respectively. At ambient conditions these parameters are 0.89 and 0.97, respectively. An inversion algorithm was used to retrieve microphysical particle properties from the extinction coefficients measured with DOAS. We found excellent agreement within the retrieval uncertainties. 相似文献
74.
Krammer GE Weckerle B Brennecke S Weber B Kindel G Ley J Hilmer JM Reinders G Stöckigt D Hammerschmidt FJ Ott F Gatfield I Schmidt CO Bertram HJ 《Molecular nutrition & food research》2006,50(4-5):345-350
In the past flavor research and the development of new flavorings were constantly driven by the interaction of flavor analysis, structure elucidation, and chemical synthesis accompanied by sensory. Highly potent flavor compounds were identified in numerous food products and helped to establish a powerful toolbox for flavorists. Nowadays we experience the merging of various scientific disciplines, for example medicine, biology, chemistry, and various technologies in the field of flavor research, which shows direct impact on our understanding of flavors. At the same time modern life has profoundly changed our eating habits. This situation generates new challenges for product development teams, which represent all facets of technologies. This paper will illustrate different examples for the evolution of product-oriented flavor research and future trends. 相似文献
75.
The development of electric mobility systems with fuel cells is associated with a special constellation of circumstances. The definition of powertrain systems on board electric vehicles is dependent on the refueling infrastructure. At the same time, the development of a hydrogen infrastructure is dependent on vehicle definition and introduction. The joint development of powertrain and infrastructure is a unique opportunity to optimize both the systems. In this paper, we select a number of tradeoffs between the powertrain design and the infrastructure design and calculate technical and financial effects. By way of example we show an optimization of the fuel cell, battery and tank size subject to user behavior and infrastructure constraints. Using powertrain simulations we calculate hybridization ratio and tank size. We then show an exemplary infrastructure layout consisting of transmission and distribution networks. In this paper we consider the infrastructure in Germany by 2030. We then proceed to show the implications of the mutual dependencies between vehicle and infrastructure and to analyze technical potentials and overall system costs. Our main conclusions show ways that could be beneficial for the introduction of electric mobility with fuel cells and a hydrogen infrastructure. 相似文献
76.
Laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) is a powerful method for elemental fingerprinting of solid samples in a quasi-nondestructive manner. In order to extend the field of application to objects outside the laboratory, a portable laser ablation sampling device was assembled using a diode pumped solid state laser and fiber-optics. The ablated materials were sampled on membrane filters and subsequently quantified by means of LA-ICPMS. The analytical performance of this approach was investigated for glass and gold reference materials. Accuracies of better than 20% were reached for most elements and typical limits of detection were found to be in the range of 0.01-1 μg/g. In summary, this approach combines spatially resolved sampling with the detection power of ICPMS and enables elemental fingerprinting of objects which cannot be transferred to the laboratory, e.g., archeological artifacts in museums. 相似文献
77.
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79.
Uncertainties in energy demand modelling allow for the development of different models, but also leave room for different calibrations of a single model. We apply an automated model calibration procedure to analyse calibration uncertainty of residential sector energy use modelling in the TIMER 2.0 global energy model. This model simulates energy use on the basis of changes in useful energy intensity, technology development (AEEI) and price responses (PIEEI). We find that different implementations of these factors yield behavioural model results. Model calibration uncertainty is identified as influential source for variation in future projections: amounting 30% to 100% around the best estimate. Energy modellers should systematically account for this and communicate calibration uncertainty ranges. 相似文献