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121.
Seda Karasu Yalcin 《Food science and biotechnology》2012,21(3):867-874
In order to enhance citric acid production by Yarrowia lipolytica 57, mutation and selection treatments were performed by using UV-irradiation and/or ethyl methane sulfonate (EMS) as a chemical mutagen. Totally 18 mutant strains were demonstrated by testing of 1,234 colonies and then used in citric acid production studies. Chemical mutagenesis was found as more effective in enhancing citric acid production than UV-induced mutagenesis. Maximum citric acid concentration (50.1 g/L) and yield obtained by the chemical mutant Y. lipolytica K-168 exceeded that of the initial strain by 57%. Growth and citric acid production of this strain was further examined in natural fermentation media containing carrot juice or celery byproducts. Maximum citric acid concentration reached to 62.6 g/L in diluted carrot juice medium supplemented with glucose. It was determined that enriched carrot juice may serve as a good nutrient source and could be used for citric acid production by K-168 strain. 相似文献
122.
Nermin Seda Kehr Kristina Riehemann Jehad El‐Gindi Andreas Schäfer Harald Fuchs Hans‐Joachim Galla Luisa De Cola 《Advanced functional materials》2010,20(14):2248-2254
Chemically functionalized self‐assembled monolayers made by disk‐shaped zeolite L nanocrystals are used as models for biocompatible surfaces to study cell‐adhesion behavior. Different chemical groups lead to different cellular behavior and fluorescent‐molecule‐loaded zeolites allow the position of the cells to be determined. Furthermore, a patterned monolayer of asymmetrically functionalized zeolite L obtained by microcontact chemistry is used to grow cells. A spatial recognition of the cells, which proliferate only on the bioactive‐molecule‐functionalized stripes, is possible. 相似文献
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The effects of the various salts onto the emulsifier‐free emulsion polymerization of methyl methacrylate (MMA) were investigated. It was found that the kind and amount of the salts were very effective on the polymerization even onto the polymeric products. It is known that the ionic strength of the electrolyte is effective for the polymerization. However, our investigation with the same ionic strength of different electrolyte produced the different effect on the polymerization. It was found that the Stokes radiuses of ions are very important for the reaction kinetics and type of the product. At the same electrolyte concentration, as increased Stokes radii of cation of salts that not react (the fragments of initiator, ions, etc.) in polymerization, polymerization rate and average molecular weight of polymer decreased, polymer particle diameter increased. In the case of Br? and SO4= the anions of the salt are also demonstrated some unexpected reactions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2494–2500, 2007 相似文献
125.
M.M. Dardir Hany Elsayed Ahmed M. Abd El Fattah Mohammed Ezz El Din Rashad Hassan Hesham Abu Seda Mohammed Gad Elsonbatty 《Egyptian Journal of Petroleum》2018,27(4)
The objective of drilling operation is to drill, evaluate and complete a well that will produce oil and/or gas efficiently. The responsibility for performing these functions is held by using drilling mud.The research will focus on the oil base mud system due to the importance of that kind of drilling fluid which helped to address several drilling problems such as formation clays that react, swell or slough after expose to WBFs, increasing down hole temperatures, contaminants, stuck pipe, torque and drag.The research will rely on an economical-low cost prepared emulsifiers that used as W/O emulsifiers for oil base mud instead of the imported emulsifier. The new prepared emulsifiers provide an excellent options with emulsification power for oil-based mud that formulated from diesel oil and water.The nonionic emulsifiers were prepared through the esterification reaction of propylene glycol (1?mol) and stearic acid (1?mol) and/or (2?mol), the products were two oil soluble nonionic emulsifiers with hydrophilic/lipophilic balance (HLB) of 3.4 and 2.8 respectively. The chemical structure was confirmed using elemental analysis, FTIR and 1H NMR.The new prepared emulsifiers were evaluated as primary emulsifiers for oil – base mud and the results were compared with the currently used primary emulsifier. The obtained results exhibited interesting rheology properties and shear-thinning behavior, yield value, thixotropy, gel strength and filter loss. 相似文献
126.
Ethylene‐propylene‐diene‐monomer (EPDM) rubber is an important commercial polymer. The vulcanization process significantly changes its thermal, mechanical, and vulcametric properties. This study was carried out to find optimum formulation of EPDM composite for a better application in automotive industry. Sixteen EPDM polymer samples having different 5‐ethylidene 2‐norbornene (ENB) and ethylene contents were vulcanized with different types and compositions of peroxide and coagents. The mechanical and vulcametric properties of these samples were measured and compared. The type of peroxide, coagent, and EPDM grade affected the mechanical, thermal, and vulcametric properties of the EPDM rubber to some extend. Use of aromatic peroxide and coagent increased the thermal stability slightly. Mechanical properties were changed very slightly with the change of peroxide type for the same content of peroxide and coagent. Scorch time and cure time decreased with initial increase of the peroxide content. EPDM compound vulcanized with BBPIB peroxide and TAC/S coagent has higher cure time than EPDM compound vulcanized with DMBPHa peroxide and TMPTMA coagent. Coran method was used for the modeling of experimental data. Velocity constant for the formation of peroxide radical and polymer radical were found for each case. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
127.
Effects of gelatinisation level, gum and transglutaminase on the quality characteristics of rice noodle 总被引:2,自引:1,他引:1
The aim of the present study was to investigate the effects of gelatinisation level, gum (locust bean gum, xanthan gum, 3%) and/or transglutaminase (TG, 0.5%) on quality characteristics of rice noodle. In order to improve the dough forming ability, rice flour was gelatinised at levels of 15%, 20%, 25% and 30%. Noodle samples were evaluated in terms of cooking loss, total organic matter (TOM), water absorption, swelling volume, maximum force, colour, sensory properties, pasting properties. Noodle sample with a gelatinisation level of 25% had better cooking and sensory properties. Gum and/or TG were added to this noodle formula. The noodle samples including xanthan gum had better cooking and sensory properties. TG caused a significant decrease in TOM. The samples including locust bean gum had significantly higher maximum force values. Xanthan gum caused decreases in some Rapid ViscoAnalyzer viscosity values of the noodle samples, while locust bean gum caused increases. 相似文献
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129.
A complete understanding of the reaction kinetics for the industrial production process of expandable polystyrene
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130.
Kamil Kayabali Turgay Beyaz Ersin Kolay 《Bulletin of Engineering Geology and the Environment》2006,65(1):65-71
It is known that foundation problems are caused by the dissolution of gypsum due to both chemical and mechanical processes. In order to investigate the combined effect of physico-chemical agents on the erodability of gypsum, a series of slake durability tests were carried out on eight different types of gypsum using testing solutions with different pH values. XRD, chemical and petrographical analyses, and basic strength tests such as unconfined compression, Brazilian tensile, and point load were performed on the eight rock types. The slake durability results ranged from medium to very high under the different pH conditions but it was concluded that the slake durability of gypsum is independent of the pH of the testing solution. Mineralogical composition and fabric are considered to have a greater influence on the slake durability of gypsum. 相似文献