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排序方式: 共有466条查询结果,搜索用时 15 毫秒
41.
Kankaanpää P Tuomola E El-Nezami H Ahokas J Salminen SJ 《Journal of food protection》2000,63(3):412-414
Lactic acid bacteria have been previously reported to possess antimycotoxigenic activities both in vitro and in vivo. The objective of this study was to investigate the effect of aflatoxin B1 on adhesion capability of Lactobacillus rhamnosus strain GG using a Caco-2 adhesion model. Removal of aflatoxin B1 by L. rhamnosus strain GG reduced the adhesion capability of this strain from 30% to 5%. It is therefore concluded that aflatoxins may influence the adhesion properties of probiotics able to sequester them, and subsequently these bacteria may reduce the accumulation of aflatoxins in the intestine via increased excretion of an aflatoxin-bacteria complex. 相似文献
42.
Variation in α‐acetolactate production within the hybrid lager yeast group Saccharomyces pastorianus and affirmation of the central role of the ILV6 gene
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43.
Jukka Ekberg Brian Gibson Jussi J. Joensuu Kristoffer Krogerus Frederico Magalhães Atte Mikkelson Tuulikki Seppänen‐Laakso Arvi Wilpola 《Journal of the Institute of Brewing》2015,121(4):464-473
Sahti, a strong, unhopped farmhouse beer flavoured with juniper, is still actively brewed in rural areas in Finland. Presented here is the first comprehensive analysis of the physical and chemical properties of this unique beer style. Twelve sahti samples from the southwest of Finland were analysed and, while properties varied, the beers generally had high levels of alcohol (mean = 7.9% ABV) and high residual extract (mean = 9.5°P). Foam stability was negligible, as is typical for the style, and glycerol concentrations at 3.1 – 4.7 g L?1 were higher than in reference beers (commercial lager, wheat beer and porter). These features may be attributed to the very high gravity conditions employed in brewing sahti beers. Bitterness levels were relatively low (3–13 IBU) owing to the absence or moderate use of hops. All samples contained detectable levels of the clove‐like compound 4‐vinylguaiacol owing to the use of baker's rather than brewer's yeast for brewing. Concentrations of higher alcohols and esters were high, with many individual aroma compounds being above the normal flavour thresholds. Results have highlighted the uniqueness of this style of beer in comparison to commercially available beers and have contributed to our understanding of the reasons for the particular sensorial properties of this traditional beer style. Copyright © 2015 The Institute of Brewing & Distilling 相似文献
44.
Isosaari P Kankaanpää H Mattila J Kiviranta H Verta M Salo S Vartiainen T 《Environmental science & technology》2002,36(12):2560-2565
Dated sediment cores and surface sediments were analyzed from the Gulf of Finland, a part of the Baltic Sea, to study the sources, levels, distribution, and total amounts of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). The gulf was found to be severely polluted, with PCDD/F sum concentrations as high as 101000 ng/kg and 479 ng/kg WHO-TEQ in dry weight. The source of pollution was the former manufacturing and use of a chlorophenol based wood preservative along the Kymijoki River. It was estimated thatthe impacted sedimentary area stretched a distance of 75 km away out from the coast and that the PCDD/F sum load attributed to the wood preservative source was 1770 kg of PCDD/Fs or 12.4 (+/-2.8) kg WHO-TEQ. The surface sediments contained 24-66% of the maximum concentrations present in the 1960-1970s, showing that the river still acts as a significant PCDD/F source and may contribute to the high levels in fish. Moreover, the reduced PCDD/F and PCB concentrations were partly due to the dilution by increased dry matter deposition. PCBs were uniformly distributed over the gulf, and the PCB load in the polluted area was 2020 kg or 0.14 kg WHO-TEG. 相似文献
45.
Tommy Munk Stefania Baldursdottir Sami Hietala Thomas Rades Markus Nuopponen Katriina Kalliomäki Heikki Tenhu Jukka Rantanen Clare J. Strachan 《Polymer》2013
The use of vibrational spectroscopy to investigate complex structural changes in polymers yields chemically rich data, but interpretation can be challenging and subtle but meaningful spectral changes may be missed through visual inspection alone. Multivariate analysis is an efficient approach to gain an oversight of small but systematic spectral differences anywhere within the spectra, providing further insight into structural changes and associated transformation mechanisms. In this study, the novel analytical approach of infrared spectroscopy combined with principal component analysis and Gaussian peak fitting was used to investigate the structural changes in aqueous solutions of a polymer, using poly(N-isopropyl acrylamide) (PNIPAM) in the atactic form and with controlled tacticity as a model system. Subtle spectral changes associated with the dehydration and phase separation upon heating included peak shifts, an area ratio change of the amide I band to the amide II band and formation of a new peak in the amide I band were efficiently detected. Dehydration and phase separation of PNIPAM occurred in two temperature ranges, one for the atactic and one for isotactic rich part, both involving a complex re-organization of the hydrogen bonds and change of the hydration layer. The changes agreed with existing results from other techniques, and new insights were gained into the effect of controlled tacticity on phase transformation behaviour. The study demonstrates that infrared spectroscopy combined with the multivariate analytical method principal component analysis and Gaussian peak fitting is an efficient approach to probing structural change in polymers during heating. The simplicity of the presented approach could find excellent use in analysing and understanding the molecular environment of a range of stimuli-responsive polymers, for instance block or grafted types of polymers, as well as those with controlled tacticity. 相似文献
46.
Identity and overall acceptance of two types of sour rye bread 总被引:1,自引:0,他引:1
Raija-Liisa Heiniö Nina Urala Jukka Vainionpää Kaisa Poutanen & Hely Tuorila 《International Journal of Food Science & Technology》1997,32(2):169-178
Response surface methodology was employed to study the influence of four recipe variables (wheat: rye flour ratio, bread acidity, ash content of rye flour and sodium chloride content) on the identity and overall acceptance of two rye bread types (soft and crisp rye bread). The subjects ( n = 79) rated attribute intensities, the extent to which the salient sensory properties and the overall sample corresponded to their expectations of rye bread, and the overall acceptance (pleasantness and purchase intentions). The acidity and ash content contributed the most to the extent to which a sample met subjects' expectations. The NaCl content was not critical. Consumer acceptance was affected by ash content, and by the interactions, NaCl content × acidity and wheat:rye ratio × ash content. The non-significance of NaCl content should encourage the baking industry to put low-salt rye products on the market. 相似文献
47.
Product development has until recently been considered pure art instead of being a controllable process. However, the current competitive environment has forced companies to take a closer look in the way new products are being developed. A key element in this assessment is the development of a set of metrics, which describe the whole product development process. This article explores the data-based opportunities for continuous improvement in the product development process emerging alongside the increasing utilization of networked Information Technology (IT) applications. Based on data from information systems in the case-study companies, three different product process visualizations are presented. Each visualization is discussed both from the viewpoint of its explanatory power as well as its limitations.The results of the case-studies clearly indicate that the computerization of the engineering and design processes is generating new ways of measuring, understanding and improving product development. The appropriate measures combined with open communication and a learning environment can be used to create a cycle of continually improving the product development process. 相似文献
48.
49.
A general kinetic model was developed to simulate the grafting of monomers such as unsaturated carboxylic acids and silanes to ethylene polymers. The polymers considered were ethylene-co-vinyl acetate (EVA), ethylene-co-butyl acrylate (EBA), and low-density polyethylene (LDPE). Grafting was assumed to proceed by a free-radical mechanism involving chain transfer. Organic peroxides having a strong tendency for hydrogen abstraction were selected as the source of primary radicals. The model simulated the grafting reaction as taking place in a single screw extruder. The residence time distribution in the extruder was experimentally determined by tracer analysis, according to which the extruder was a plug-flow reactor connected to two mixed reactors in parallel. The model is able to predict the extent of grafting in terms of predefined parameters. Comparison of model predictions with available experimental data showed slight deviations, the possible causes of which are discussed. However, the kinetic behavior expected on the basis of the input parameters was observed, and, as such, the model allowed study of the effect of process variables on grafting kinetics and provided insight into the reaction mechanism. 相似文献
50.
Jukka Veli Seppl 《应用聚合物科学杂志》1985,30(9):3545-3556
The possibility was studied of using decene-1 as comonomer with ethylene in a slurry type polymerization with Ziegler–Natta catalysts. Under the reaction conditions used decene contents remained at the 2 wt% level in ethylene/decene-1 copolymers. When additionally butene-1 was present in the polymerization, decene-1 contents were significantly higher. A synergistic effect was identified in the reactivities of butene-1 and decene-1 in terpolymerization with ethylene. The comonomer reactions were determined and comonomer contents measured by 13C-NMR spectroscopy. Decene-1 content had an effect on the polymer density and crystallinity, but virtually no effect on melting temperature. With high comonomer contents an additional melting range was identified in DSC curves at about 100°C. 相似文献