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131.
为了研究稀土氧化物与无机阻燃剂的协同作用,将氧化铈、氧化镧加入到含有铝镁复合阻燃剂的EVA/HDPE阻燃体系中,制备了含有稀土氧化物的复合阻燃材料.测定了复合材料的极限氧指数、力学性能,并对复合材料的微观形貌进行了研究.结果表明:稀土金属氧化物对无机阻燃体系有明显的协同阻燃增效作用.稀土氧化物可以改善无机阻燃剂在基体树脂中的均匀分散,复合材料的力学性能有所改善. 相似文献
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133.
通过扫描电镜(SEM)观察了水辅助注塑聚丙烯(PP)/乙烯-醋酸乙烯共聚物(EVA)共混物制品近浇口和远浇口处外表层、芯层和内表层的相形态.结果表明,分散相主要以层状分布在基体中,在两个观察位置外表层和内表层的层状分散相厚度比芯层的大,远浇口处外表层和内表层的分散相厚度比近浇口处对应层的大.从温度场和剪切场两个方面分析了分散相的形变过程. 相似文献
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The rheological properties of PC/EVA blends had been investigated by a Haake torque rheometer. The effects of blending temperature, a polycarbonate and a catalyst on the rheological properties of PC/EVA blends were discussed. The transesterification between PC and EVA, catalyzed by dibutyl tin oxide (DBTO), were investigated by differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). The results indicate that the chain break of PC or EVA can be accelerated by DBTO, which induces the equilibrium torque of PC or EVA to decrease as the DBTO content increases. But for the PC/EVA blend, as the blending temperature of increases, the increase of viscosity induced by the generation of the PC-EVA copolymer exceeds the decrease of viscosity induced by the chain break of PC and EVA. Therefore, the equilibrium torque of the PC/EVA blend with varying DBTO content is higher than that of uncatalyzed PC/EVA blend at the higher temperature, 250°C, compared with the lower temperature, 210°C. The content of PC in the blend influences the probability of transesterification and the generation of PC-EVA copolymer. The PC/EVA blend with 50 wt. %PC has the highest torque compared with the other blends. 相似文献
137.
H. Ardhyananta H. Ismail T. Takeichi H. Judawisastra 《Polymer-Plastics Technology and Engineering》2013,52(12):1285-1293
Ethylene vinyl acetate (EVA)/organoclay/compatibilizer nanocomposites were produced using a melt compounding technique in an internal mixer, Haake Rheometer, at 120°C and 50 rpm rotor speed. Effects of organoclay loading (from 2 to 10 phr—parts per hundred of resin and methyl ethyl ketone (MEK), used as a compatibilizer, on the processing properties, tensile properties, morphology, thermal degradation, and water absorption behavior of EVA/organoclay nanocomposites were studied. Results indicate that the presence of organoclay increase the processing torque, tensile properties, thermal degradation, and resistance to water absorption. The optimum organoclay loading was achieved at 2 phr. This was caused by the dispersion state of individual silicate layers (intercalation/exfoliation) in EVA matrix. The intercalation/exfoliation structure affects the properties of EVA/organoclay nanocomposites as evidenced from the morphology studies such as x-ray diffraction (XRD) and transmission electron microscopy (TEM) evaluation. The addition of MEK has the ability to improve the tensile properties, thermal degradation, and slightly reduces the resistance of water permeation of EVA/organoclay nanocomposites. The enhanced properties were seen as a result of the better matrix and filler interaction. The EVA/organoclay/MEK nanocomposites shows better intercalation/exfoliation of individual silicate layers in the EVA matrix as indicated by TEM. Moreover, the XRD evaluation shows that intercalation/exfoliation of the organoclay was formed in the EVA matrix. 相似文献
138.
Kun Wu 《Polymer-Plastics Technology and Engineering》2013,52(3):247-254
With a melamine-formaldehyde (MF) resin coating layer, microencapsulated ammonium polyphosphate (MCAPP) is prepared by in situ polymerization and is characterized by XPS and water leaching test. The microencapsulation of APP with the MF resin leads to a decrease in the particle's water leaching rate. The flame-retardant action of MCAPP and APP in EVA are studied using LOI and UL 94 test, and their thermal stability is evaluated by thermogravimetric analysis (TGA). The LOI value of the EVA/MCAPP composite at the same loading is higher than the value of the EVA/APP composite. In comparison with the EVA/MCAPP composites, it is found that the LOI values of the EVA/MCAPP/PER and EVA/MCAPP/DPER ternary composites at the same additive loading increase, and UL 94 ratings of most ternary composites are raised to V-0. The water-resistant properties of the EVA composites are studied, and the results of the composites containing with APP and MCAPP are compared. Moreover, the peroxide cross-linking of the EVA composites is investigated, and the mechanical properties and thermal stability of the composites increase after the cross-linking. 相似文献
139.
《Journal of Adhesion Science and Technology》2013,27(8):1145-1159
Two ethylene vinyl acetate (EVA) copolymers (12 and 20 wt% of vinyl acetate,VA, content) have been treated with low pressure RF plasmas from non-oxidizing gases (Ar, N2) and oxidizing gases (air, a mixture of 4N2: 6O2 (v/v), O2 and CO2). The formation of polar moieties on both EVAs was more noticeable by treatment with plasmas from non-oxidizing gases than from oxidizing ones (the higher the reactivity, the lower the difference with respect to untreated EVA surfaces). The surface etching with the non-oxidizing plasmas, giving rise to a high roughness, depends on the wt% of VA in the composition of the copolymer because of the different resistances of VA (low) and PE (high) to the non-oxidizing plasma particles bombardment. The adhesion properties obtained using a polyurethane adhesive (PU) showed high T-peel strength values and adhesion failure in EVAs treated with plasmas from oxidizing gases, due to roughness produced causing mechanical interlocking of the adhesive. Lower T-peel strength values were obtained with non-oxidizing plasmas: the values for EVA12 being, in general, lower than those obtained for EVA20. The durability of the treated EVAs/PU adhesive joints after ageing in humidity and temperature was quite good. 相似文献
140.
《Journal of Adhesion Science and Technology》2013,27(13):1831-1845
A series of ethylene vinyl acetate (EVA) copolymers were blended with aromatic hydrocarbon resins in the molten state in various ratios and possible relations between viscoelastic and adhesion properties as hot-melt adhesives (HMAs) were investigated. When the softening point of aromatic hydrocarbon resin was high and the concentration of aromatic hydrocarbon resin was low, the tan δ peak height decreased and broadened. This result corresponds to the miscibility of the blend. The single lap shear strength increased with increasing softening point of the aromatic hydrocarbon resin and it reached a maximum value with increasing temperature. A large scatter was observed in lap shear strength values, which were higher at higher test rates and lower temperatures, and under these conditions interfacial failure occurred. 相似文献