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101.
Three alternate dying methods—vacuum drying (VD), vacuum microwave drying (VMD), and pulse-spouted vacuum–microwave drying (PSVMD)—were examined experimentally for their potential as an industrial scale technology to produce granules of fish. Drying kinetics as well as key quality parameters such as expansion ratio, texture, color, sensory characteristics, and microstructure of crispy granules produced by these drying techniques were examined. Results showed that the drying time is reduced with an increase in microwave power level and with reduced pressure as expected. The quality of the granules is affected by the drying method and the operating parameters employed. Granules obtained using PSVMD at a microwave power density of 6.0 W/g displayed optimal quality required for the commercial product accepted by consumers. 相似文献
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为保证发射机高压电源在各种气象条件下都能正常工作,需对其电路中的高压电容进行涂覆防护.高压电容使用醇酸清漆涂覆工艺,因其操作方法较为繁琐,并且不符合环保要求,需使用新的涂覆工艺.介绍了聚对二甲苯真空涂覆的特点,并和用醇酸清漆涂覆的高压电容进行了对比试验,并全面比较了两种涂覆工艺方法,从而确定了聚对二甲苯真空涂覆工艺的可行性. 相似文献
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通过对制盐生产实际问题的改造及分析,找出影响制盐生产的各种因素及相互关系,并在实际中解决、控制,从而有效地提高制盐生产的产量,降低消耗,促进制盐企业生产技术水平的发展。 相似文献
108.
P. García-Segovia 《LWT》2011,44(2):480-488
Air-dried Shiitake mushroom (Lentinus edodes) caps were rehydrated using conventional and vacuum techniques, at different temperatures (30, 40, 50 and 80 °C) and times (1, 2, 3, 6, 9, 12, 15, 18, 21, 120, 150 and 210 min). Three empirical models were used to model the rehydration process: 1st order kinetics, Peleg’s model and the Weibull distribution function. To determine the effects of temperature and pressure on the mushroom caps, the texture of the rehydrated material was determined, evaluating peak shear force and microstructure using cold-stage scanning electron microscopy (cryo-SEM). The rehydration of the mushrooms was found to be temperature and pressure-dependant. The speed of vacuum rehydration was faster compared to conventional rehydration. When rehydrated at 80 °C, a loss in rehydration capacity was observed in both cases, which can be explained by the structural damage and cell shrinkage which occurred during air-drying. Also, the vacuum rehydrated samples had the lowest toughness values. It was concluded that vacuum rehydration of dried Shiitake mushroom caps could be a feasible alternative to the conventional rehydration process, resulting in a lower immersion time and in a desirable texture. 相似文献
109.
Silva AR Paulo EN Sant'Ana AS Chaves RD Massaguer PR 《International journal of food microbiology》2011,148(3):156-163
The objectives of this study were to isolate psychrotrophic clostridia from Brazilian vacuum-packed beef cuts (spoiled or not) and to identify the isolates by using 16S rRNA gene sequencing. Anaerobic psychrotrophic microorganisms were also enumerated and samples were collected to verify the incidence of psychrotrophic clostridia in the abattoir environment. Vacuum-packed beef cuts (n = 8 grossly distended and n = 5 non-spoiled) and environmental samples were obtained from a beef packing plant located in the state of São Paulo, Brazil. Each sample was divided in three subsamples (exudate, beef surface and beef core) that were analyzed for vegetative forms, total spore-forming, and sulfide reducing spore-forming, both activated by alcohol and heat. Biochemical profiles of the isolates were obtained using API20A, with further identification using 16S rRNA gene sequencing. The growth temperature and the pH range were also assessed. Populations of psychrotrophic anaerobic vegetative microorganisms of up to 1010 CFU/(g, mL or 100 cm2) were found in ‘blown pack’ samples, while in non-spoiled samples populations of 105 CFU/(g, CFU/mL or CFU/100cm2) was found. Overall, a higher population of total spores and sulfide reducing spores activated by heat in spoiled samples was found. Clostridium gasigenes (n = 10) and C. algidicarnis (n = 2) were identified using 16S rRNA gene sequencing. Among the ten C. gasigenes isolates, six were from spoiled samples (C1, C2 and C9), two were isolated from non-spoiled samples (C4 and C5) and two were isolated from the hide and the abattoir corridor/beef cut conveyor belt. C. algidicarnis was recovered from spoiled beef packs (C2). Although some samples (C3, C7, C10 and C14) presented signs of ‘blown pack’ spoilage, Clostridium was not recovered. C. algidicarnis (n = 1) and C. gasigenes (n = 9) isolates have shown a psychrotrophic behavior, grew in the range 6.2-8.2. This is the first report on the isolation of psychrotrophic Clostridium (C. gasigenes and C. algidicarnis) in Brazil. This study shows that psychrotrophic Clostridium may pose a risk for the stability of vacuum-packed beef produced in tropical countries during shelf-life and highlights the need of adopting control measures to reduce their incidence in abattoir and the occurrence of ‘blown pack’ spoilage. 相似文献
110.
为了解决速溶茶粉的滋味淡、香气低、冷溶性差等问题,该试验以红茶为原料,采用高压脉冲电场(Pulsed Electric Field,PEF)技术辅助提取和杀菌,并结合冷冻浓缩和真空冷冻干燥联合真空吸附干燥法生产速溶红茶粉,使得整个加工工艺都在低温状态下完成。试验结果表明,高压脉冲电场技术有助于提高红茶的提取率,冷冻浓缩和高压脉冲电场杀菌能够有效保持茶汤的色、香、味;真空冷冻干燥联合真空吸附干燥后所得的速溶红茶粉的得率为22.7%,且其冷溶性高,滋味鲜浓而醇厚,香气高而纯正,汤色红艳明亮,无沉淀。 相似文献