全文获取类型
收费全文 | 1574篇 |
免费 | 94篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 192篇 |
综合类 | 46篇 |
化学工业 | 119篇 |
金属工艺 | 18篇 |
机械仪表 | 65篇 |
建筑科学 | 12篇 |
矿业工程 | 108篇 |
能源动力 | 56篇 |
轻工业 | 895篇 |
水利工程 | 12篇 |
石油天然气 | 10篇 |
武器工业 | 7篇 |
无线电 | 46篇 |
一般工业技术 | 12篇 |
冶金工业 | 35篇 |
自动化技术 | 45篇 |
出版年
2024年 | 8篇 |
2023年 | 11篇 |
2022年 | 42篇 |
2021年 | 34篇 |
2020年 | 42篇 |
2019年 | 40篇 |
2018年 | 42篇 |
2017年 | 46篇 |
2016年 | 60篇 |
2015年 | 73篇 |
2014年 | 81篇 |
2013年 | 97篇 |
2012年 | 126篇 |
2011年 | 124篇 |
2010年 | 89篇 |
2009年 | 57篇 |
2008年 | 72篇 |
2007年 | 110篇 |
2006年 | 112篇 |
2005年 | 86篇 |
2004年 | 68篇 |
2003年 | 64篇 |
2002年 | 48篇 |
2001年 | 29篇 |
2000年 | 25篇 |
1999年 | 21篇 |
1998年 | 25篇 |
1997年 | 11篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 4篇 |
排序方式: 共有1678条查询结果,搜索用时 15 毫秒
151.
152.
隔爆兼本质安全型低压交流电机软启动器的结构分析 总被引:1,自引:0,他引:1
根据当前国内工矿企业发展的现状,对煤矿井下使用的电动机及其拖动系统所存在的问题进行分析,提出使用软启动器的必要性,对矿用隔爆兼本质安全型低压交流电机软启动器(以下简称“防爆软启动器”)的产品结构特点、工作原理、功能特性等进行论述。 相似文献
153.
双凸极电机励磁回路控制模式的研究 总被引:1,自引:1,他引:0
电励磁双凸极起动/发电机在恒转矩起动阶段为使输出转矩最大,通常将恒定电压直接加在励磁绕组上,使励磁电流工作在最大饱和值,并认为维持不变。但在实际过程中由于励磁磁场与相绕组磁场的耦合,导致励磁电流受相电流、转速影响而被削弱,引起输出转矩的降低。该文通过理论与仿真分析了起动过程恒励磁电压控制模式下励磁电流的变化规律,并通过实验验证了起动过程相电流、转速对励磁电流的影响,在此基础上对电励磁双凸极电机恒转矩起动阶段提出励磁电流控制的方法,仿真与实验结果均表明电励磁双凸极起动/发电机励磁回路在恒转矩起动阶段必须在恒励磁流控制模式下以保证输出转矩恒定。 相似文献
154.
Birhanu Bekele Egon B. Hansen Mitiku Eshetu Richard Ipsen Yonas Hailu 《Journal of dairy science》2019,102(2):1108-1115
This experiment was conducted to investigate the effect of starter cultures on the physicochemical properties, texture, and consumer preferences of soft white cheese (SWC) made from camel (Camelus dromedarius) milk. The experiment was laid out in a completely randomized design with 5 treatments [starter cultures; i.e., 1 thermophilic (STI-12), 2 blended (RST-743 and XPL-2), and 2 mesophilic (R-707 and CHN-22) cultures]. Starter cultures STI-12 and RST-743 were inoculated at 37°C, whereas XPL-2, R-707, and CHN-22 were inoculated at 30°C. Camel milk inoculated using STI-12 and RST-743 cultures resulted in faster acidification than XPL-2, R-707, and CHN-22 cultures. Camel milk SWC made using STI-12 and CHN-22 cultures gave lower pH (4.54) and titratable acidity (0.59), respectively, whereas R-707 culture resulted in high cheese yield (13.44 g/100 g). In addition, high fat (20.91 g/100 g), protein (17.49 g/100 g), total solids (43.44 g/100 g), and ash (2.40 g/100 g) contents were recorded for SWC made from camel milk made using RST-743 culture. Instrumental analysis of cheese texture revealed differences in resistance to deformation in which camel milk SWC made using RST-743 culture gave higher firmness (3.20 N) and brittleness (3.12 N). However, no significant difference was observed among camel milk SWC adhesiveness made using different starter cultures. Consumer preference for appearance, aroma, taste, and overall acceptances of SWC were affected by inoculation of starter cultures. Considering curd firmness, cheese yield, compositional quality, and textures using STI-12, RST-743, and R-707, these cultures were found to be better for the manufacture of camel milk SWC. 相似文献
155.
Hasitha Priyashantha Alfonso Prez Quintns Raquel Baixauli Janak K. Vidanarachchi 《Journal of texture studies》2019,50(6):482-492
Organoleptic properties of skimmed milk fermented gels are progressively demanding to produce optimal quality yogurts. Chr‐Hansen trademark registered cultures were used to produce low‐protein (3.4%) gels to assess the ability to redesign the sensorial and textural properties with the choice of starter culture. Resulting gels were assessed for sensorial, textural, rheological, and microstructural properties and compared with a commercial control (4.5% protein). Mouth thickness, syneresis, firmness, elasticity, and consistency values were lower for polysaccharides‐producing cultures. Such cultures contributed to the higher creaminess and tended to give higher ropiness. Observed differences among microstructures of the gel were minute. Microstructural and rheological data corresponded and reflected the instrumental and sensory interpretations. Strong correlations were observed between sensory and instrumental data. Nonprobiotics cultures resulted in promising overall gel properties compared with probiotic cultures according to the principal component analysis. Yet probiotic cultures resulted in lower syneresis than nonprobiotic cultures. Thus, the choice of bacterial culture modifies the sensorial and textural properties of fermented gel with strong correlations, as a result of altered gel network formation with the production of polysaccharides. Inferior textural and sensorial quality aspects, particularly at low protein levels, have negative impact on consumer demand of low protein yogurts. Thus, we attempted to gain required gel textural and sensorial properties with a choice of starter culture with a low protein level. Resulting gel properties at lowered protein content with different starter cultures are not fully known. The present study compares the effect of probiotic and nonprobiotic starter cultures on gel properties, as gel texture and sensory properties are of great interest and thus not willing to be compromised. In addition, we examined the overall texture profile of studied cultures and correlate with sensory properties. Therefore, reducing protein level in milk and achieving required gel properties with the choice of appropriate starter culture is of great commercial interest as a cost‐cutting strategy to produce low‐cost optimum quality yogurt. 相似文献
156.
Kaizheng Zhang Qiong Li Wenchi Wu Jiangang Yang Wei Zou 《Journal of food science》2019,84(9):2373-2386
Chinese rice wine (CRW) is an ancient wine with a moderate alcohol content; it has been prized in China for its color, sweet flavor profile, and is a national beverage typically used in banquets. Wheat Qu is the starter used to make CRW, and plays a vital role in the quality and flavor profile. This review details the raw materials and the wheat Qu manufacturing process, and recent information on wheat Qu microbiotas. The volatile compounds in wheat Qus and its flavor are also reviewed. Finally, the enzymes, and metabolites contained in wheat Qu, such as biogenic amines, are also discussed. 相似文献
157.
158.
针对纯种根霉(Rhizopus)米粉种曲制备过程中缺乏系统控制、质量难以稳定的问题,研究其关键影响因素,优化种曲的制备工艺。以一级籼米米粉为原料,接种纯种根霉制备种曲,在单因素试验的基础上,以种曲的试饭糖分值为响应指标,利用Box-Behnken响应面设计试验优化种曲制作工艺,确定纯种根霉米粉种曲的最佳制备工艺为试管菌种培养时间72 h、二级种曲培养温度32 ℃、米粉水分含量25%。在此最佳工艺条件下进行验证试验,实际测得种曲的试饭糖分平均值为27.18 g/100 g,与模型的理论预测值非常接近,拟合成功;该模型优化工艺可为纯种根霉曲的生产提供参考。 相似文献
159.
160.