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排序方式: 共有2308条查询结果,搜索用时 31 毫秒
21.
用火焰原子吸收分光光度法研究了酵母菌对Cu2 的生物吸附作用.酵母菌能有效结合Cu2 ,10 min即可达到吸附平衡.pH为5~6时吸附效果较好.盐度及Ca2 、Na 等离子对吸附量稍有影响,升温有利于吸附.随着初始Cu2 浓度的升高,吸附量也逐渐增大.该吸附符合Langmuir等温吸附方程,最大吸附量和表观吸附平衡常数分别为1.32 mg·g-1、0.189 L·mol-1. 相似文献
22.
Beer Clarification by Novel Ceramic Hollow‐Fiber Membranes: Effect of Pore Size on Product Quality 下载免费PDF全文
In this work, the crossflow microfiltration performance of rough beer samples was assessed using ceramic hollow‐fiber (HF) membrane modules with a nominal pore size ranging from 0.2 to 1.4 μm. Under constant operating conditions (that is, transmembrane pressure difference, TMP = 2.35 bar; feed superficial velocity, vS = 2.5 m/s; temperature, T = 10 °C), quite small steady‐state permeation fluxes (J*) of 32 or 37 L/m2/h were achieved using the 0.2‐ or 0.5‐μm symmetric membrane modules. Both permeates exhibited turbidity <1 EBC unit, but a significant reduction in density, viscosity, color, extract, and foam half‐life with respect to their corresponding retentates. The 0.8‐μm asymmetric membrane module might be selected, its corresponding permeate having quite a good turbidity and medium reduction in the aforementioned beer quality parameters. Moreover, it exhibited J* values of the same order of magnitude of those claimed for the polyethersulfone HF membrane modules currently commercialized. The 1.4‐μm asymmetric membrane module yielded quite a high steady‐state permeation flux (196 ± 38 L/m2/h), and a minimum decline in permeate quality parameters, except for the high levels of turbidity at room temperature and chill haze. In the circumstances, such a membrane module might be regarded as a real valid alternative to conventional powder filters on condition that the resulting permeate were submitted to a final finishing step using 0.45‐ or 0.65‐μm microbially rated membrane cartridges prior to aseptic bottling. A novel combined beer clarification process was thus outlined. 相似文献
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The aim of this paper is to study the emerging craft beer industry from a consumer preference perspective. The craft beer industry is one of the growing segments in the beverage industry and its increasing popularity also affects individuals’ commercial beer preferences and consumption trends, although no empirical study has yet been carried out in Europe on this topic. Our exploratory study is aimed at comparing the “purely” commercial beer consumer profile with that of commercial beer consumers who have already tasted craft beers. It was observed that aroma and perceived quality, as well as the preference for draft beer, drinking beer frequently or by oneself are all factors that explain the propensity of “purely” commercial beer drinkers to taste craft beer. It was also found that beer consumers’ evaluations of characteristics and brands differed depending on whether they had previously tasted craft beer or not. Moreover, craft beer is chosen according to different flavor preferences compared to commercial beer, it is mainly drunk by frequent beer drinkers in pubs and with family members and it is perceived to be of higher quality than commercial beer due to the raw materials used for brewing and its overall quality. These results can help both new entrepreneurs in the craft beer segment as well as big manufacturing firms in trying to better understand this new consumption trend in order to meet the new needs and preferences of beer consumers. 相似文献
24.
Arup Jyoti Das Prerna Khawas Tatsuro Miyaji Sankar Chandra Deka 《International Journal of Food Properties》2016,19(9):2087-2101
Phytochemicals content and antimicrobial activity of Artocarpus heterophyllus, Cyclosorus extensa, Oldendia corymbosa, and Alpinia malaccensis were investigated. Maximum alkaloids and terpenoids were found in A. heterophyllus; tannins and saponins in C. extensa; flavonoids, polyphenols, and phytosterols in O. corymbosa and anthraquinone, glycosides, and anthocyaninin A. malaccensis. Aqueous, methanolic, ethyl acetate, and hexane extracts were prepared from all the leaves. Attenuated total reflectance Fourier transform infrared spectrophotometric (ATR-FTIR) analysis revealed that alkanes and alkyl halides were prevalent in all the extracts and the ethyl acetate extracts contained comparatively higher number of functional groups, which were also more effective against Candida albicans, Escherichia coli, and Staphylococcus aureus. The minimum inhibitory concentration values of A. malaccensis against the tested pathogens were found to be lesser than the other species. 相似文献
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HPLC法测定麻杏止咳糖浆中苦杏仁苷的含量 总被引:1,自引:0,他引:1
建立高效液相色谱法测定麻杏止咳糖浆中苦杏仁苷含量的方法。采用KromasilC18柱,乙腈-0.1%磷酸溶液(8∶92)为流动相,流速1.0mL·min-1,检测波长207nm。苦杏仁苷在0.0406~0.812μg范围内有良好的线性关系, r=0.9999,平均回收率为99.0%,RSD为0.25%。本方法简便、准确、重现性好,可用于麻杏止咳糖浆的质量控制。 相似文献
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依据恒速过滤理论建立起管式啤酒过滤的数学模型 ,应用此方程于啤酒硅藻土过滤过程 ,可以作为管式啤酒过滤优化的理论依据。 相似文献
30.
Tomáš Horák Jiří Čulík Vladimír Kellner Marie Jurková Pavel Čejka 《Journal of the Institute of Brewing》2009,115(3):214-219
Dominant trends in analytical chemistry include miniaturization in sample preparation techniques and faster run times to provide high‐throughput screening, fast process monitoring and fast method development. This study focused on the application of narrow bore gas chromatographic capillary columns, 0.18 mm internal diameter, for brewing analyses. On these capillary columns, faster analyses could be performed compared to conventional GC capillary columns using 0.32 to 0.53 mm internal diameters. The robustness of the state‐of‐the‐art faster capillary gas chromatography, without compromising resolution, has been demonstrated with the analyses of beer flavour compounds such as lower and higher alcohols, esters and other volatile compounds such as acetaldehyde and dimethyl sulphide in beer. These methods were able to reduce sample run times by 60%. 相似文献