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41.
In the wake of recent food price spikes, plus growing demands for food in emerging Asia and for biofuels in Europe and the United States, governments are re-examining their strategies for dealing with both short-term and long-term food security concerns. This paper argues that long-run trends in real agricultural prices have policy implications for food security that are at least as important as those related to short-lived spikes around trend prices. The paper therefore summarizes recent projections of markets to 2030 under various scenarios, and then reviews evidence on how trade policy restrictions typically are altered to insulate domestic markets from short-run fluctuations in international prices around their long-run trends. That provides a firm empirical basis for re-examining the effectiveness and efficiency of various policy options for ensuring food security in Asia and elsewhere. Those options include boosting agricultural productivity growth rates to deal with long-run concerns, and using more-appropriate domestic policy measures rather than trade policies to cope with price volatility.  相似文献   
42.
The main aim of this study was to investigate consumer preferences for extrinsic attributes of iced coffee, explore consumers' coffee consumption habits, find new market opportunities and segment consumers based on similar products preferences. A sample of 101 consumers of iced coffee was recruited during 2012 in Norway. Twelve iced coffee products combining different levels of attributes such as coffee type, origin, calories and price were presented on screen and rated according to consumers' willingness to buy (WTB). Mixed model anova , principal component analysis (PCA) and partial least squares discriminant analysis (PLS‐DA) were applied to analyse data. Results show that the most preferred products for the consumer sample as a whole were low‐price low‐calorie products, while age has a significant effect on WTB for different iced coffee products. Four different consumer segments based on type of iced coffee and country of production preferences were identified and discussed.  相似文献   
43.
The influence of pasteurization on non‐filtered beers was investigated during accelerated storage (40°C, 41 days). Two beers were produced from the same hopped wort, which was fermented with two different yeast strains. Half of the bottled beers were tunnel pasteurized resulting in four different beer samples. The pasteurization influenced the volatile profile of both fresh beers, but during storage the differences between the volatile profiles of pasteurized and non‐pasteurized beers disappeared. During the storage period, the pasteurized beers gave a lower rate of radical formation, as evaluated by electron spin resonance spectroscopy, indicating a better oxidative stability. The pasteurization had no effect on the levels of the pro‐oxidative metals iron and copper. Pasteurization slightly increased the protein content of the beers. SDS–PAGE analysis showed that the two beers had different protein profiles, which changed during storage; however, pasteurization of both beers did not affect their protein profiles. The level of thiols were lowered in one beer and raised in the other beer by pasteurization, but during storage the levels of thiols decreased at the same rate in all of the beers. It was concluded that pasteurization had a positive influence on the oxidative stability of non‐filtered beer. Copyright © 2013 The Institute of Brewing & Distilling  相似文献   
44.
Malt is usually expected to be stable during 12 months of storage. However, in practice many brewers notice changes in malt aroma during storage. The oxidative stabilities of pilsner malt and roasted malt were evaluated during a 12 month storage at different temperatures (10 and 20 °C) and water activities (0.231 and 0.432). The radical content in malt kernels was measured by electron spin resonance spectroscopy and the volatile profile of the resulting sweet worts was measured by head‐space analysis followed by GC‐MS analysis. The storage of malt resulted in oxidative reactions and a large change of the volatile profile of the resulting worts. Roasted malt was much more unstable than pilsner malt, as illustrated by a higher initial radical intensity, larger radical decay during storage and a larger change in the volatile profile of the wort with increased amounts of lipid oxidation products. For both roasted malt and pilsner malt, good correlations were found between radical decay and changes in the volatile profile of the wort, where high temperature and high water activity resulted in the largest changes. During the 12 months of storage, the sugar extract of the wort made from the malts remained constant and was not affected by the chemical changes. This study suggests that chemical changes occurring in malts during less than 12 months of storage may potentially affect the aroma of beer, and that water activity and storage temperature should both be kept low in order to maintain a high malt quality. Copyright © 2014 The Institute of Brewing & Distilling  相似文献   
45.
Light-induced formation of free radicals in cream cheese   总被引:2,自引:0,他引:2  
Radicals were found, by electron spin resonance (ESR) spectroscopy, to accumulate in cream cheese (26% fat, 7% protein) and more significantly in low fat cream cheese (17% fat, 11% protein) upon light exposure. The decay of radicals following illumination (875 lux, with a strong UV-component for up to 80 min) followed first-order kinetics with a half-life at room temperature of around 0.5 h both for cream cheese and low fat cream cheese. The surprisingly long-lived radicals had a broad structureless ESR-spectrum (g-value of 2.006) which, for partly desiccated cream cheese, changed towards a nitrogen-centred ESR powder spectrum (g-value of 2.0014) typical for immobilised protein-based radicals. The protein oxidation product, dimethyl disulphide, and the lipid oxidation products, hexanal and 2-butanone, were detected by GC-analysis in higher concentrations in the outer 1 mm layer than in the second layer (of 1 mm thickness) of the product, in agreement with absorption of 99% of the UV-light intensity in the outer 1 mm layer. The low fat cream cheese had higher levels of both lipid and protein oxidation products, in agreement with the higher steady state concentration of radicals and confirming the role of proteins in oxidative changes also for lipids in cheese. The low fat cream cheese was initially more oxidised than was the cream cheese, as seen from the peroxide values, and oxidation products in lipid droplets could be visualised in three dimensions by confocal laser scanning microscopy, using the fluorescent probe C11-Bodipy (581/591).  相似文献   
46.
The emf of an electrochemical cell is interpreted by use of measurable local changes in Gibbs energy across the cell. It is shown by calculation that the contribution to emf from changes in electrostatic potentials is negligible for most conditions. The contribution is in principle measurable. This way of explaining contributions to emf is compared to the traditional interpretation in terms of sums of electrostatic potentials.  相似文献   
47.
Restoring the control of food intake is the key to obesity management and prevention. The arcuate nucleus (ARC) of the hypothalamus is extensively being studied as a potential anti-obesity target. Animal studies showed that neuropeptide FF (NPFF) reduces food intake by its action in neuropeptide Y (NPY) neurons of the hypothalamic ARC, but the detailed mode of action observed in human neurons is missing, due to the lack of a human-neuron-based model for pharmacology testing. Here, we validated and utilized a human-neural-stem-cell-based (hNSC) model of ARC to test the effects of NPFF on cellular pathways and neuronal activity. We found that in the human neurons, decreased cAMP levels by NPFF resulted in a reduced rate of cytoplasmic calcium oscillations, indicating an inhibition of ARC NPY neurons. This suggests the therapeutic potential of NPFFR2 in obesity. In addition, we demonstrate the use of human-stem-cell-derived neurons in pharmacological applications and the potential of this model to address functional aspects of human hypothalamic neurons.  相似文献   
48.
49.
The transported entropy of Na+ in mixtures of NaF (s) and Na3AlF6 (s) is determined from thermocell experiments. The experiments were favorably described by the electric work method. The variation observed in the thermocell electromotive force (emf) with composition can be explained from the probable path of charge transfer in the electrolyte. The transported entropies are S*cry Na+ = 140 ± 7 J K?1 mol?1 for cryolite and S*NaFNa+ = 81 ± 8 J K?1 mol?1 for sodium fluoride between 380 °C and 500 °C. The value obtained for sodium in the solid cryolite makes us predict that the transported entropy for Na+ in themolten electrolyte mixture for aluminum production is substantial and that the reversible heat effects in the aluminum electrolysis cell are the same.  相似文献   
50.
Specific legislation in the EU requires that foods containing more than 0.9% of genetically modified organisms (GMOs) should be labelled. This has necessitated the development of methods for detection and quantification of such materials. Here we present a robust, quantitative, 9-plex PCR method for event-specific detection of maize TC1507, MON863, MON810, T25, NK603, GA21, construct specific detection of BT11, BT176 and detection of the endogenous hmga maize reference gene. The method is suitable for quantification in the 0–2% range with a detection limit of approximately 0.1%. PCR is carried out in two stages. In the first stage, bipartite primers containing a universal 5′-sequence and a GMO specific 3′-sequence are used. In the second PCR stage only a universal primer is used. Trypsin digestion between the first and second PCR stages enhances signal strength and reproducibility. Probes hybridising to the PCR amplicons are then labelled by primer extension and detected by fluorescence capillary electrophoresis. Good agreement was observed in 76 of 80 determinations when 10 food and feed samples were analysed using the multiplex PCR assay and compared to results from quantitative real-time 5′-nuclease PCR. The presented method is therefore suitable for quantification purposes for food and feed containing the most common maize GMOs.  相似文献   
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