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81.
Computing global illumination by finite element techniques usually generates a piecewise constant approximation of the radiosity distribution on surfaces. Directly displaying such scenes generates artefacts due to discretization errors. We propose to remedy this drawback by considering the piecewise constant output to be samples of a (piecewise) smooth function in object space and reconstruct this function by applying a binary subdivision scheme. We design custom taylored subdivision schemes with quadratic precision for the efficient refinement of cell- or pixel-type data. The technique naturally allows to reconstruct functions from non-uniform samples which result from adaptive binary splitting of the original domain (quadtree). This type of output is produced, e.g., by hierarchical radiosity algorithms. The result of the subdivision process can be mapped as a texture on the respective surface patch which allows to exploit graphics hardware for considerably accelerating the display. 相似文献
82.
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84.
Petra Schwendig und Hans-Peter Thier 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1989,188(1):1-6
Zusammenfassung Eine Analysenmethode wird beschrieben, mit der Methylcellulose aus Lebensmitteln isoliert, identifiziert und quantitativ bestimmt werden kann. Dickungsmittel natürlicher Herkunft werden zunächst durch Fällung mit Ethanol abgetrennt und können anschließend getrennt weiter untersucht werden. Je nach der Zusammensetzung des Lebensmittels entfernt man Proteine, Fett und restliche Stärke und isoliert die Methylcellulose durch Fällung mit Tannin oder auch durch Gelchromatographie. Nach Hydrolyse mit Salzsäure werden die gebildeten Methylglucosen durch Gaschromatographie an einer Glascapillarsäule als Trimethylsilyloxime getrennt. Aus der Summe der Bausteine läßt sich der Gehalt an Methylcellulose und deren Methylierungsgrad berechnen. Die Bestimmungsgrenze lag bei Zusatzversuchen zu Milchprodukten bei 0,02 g/100 g und zu Fruchterzeugnissen, Wein und Bier bei nur 0,005 g/100 g (Wiederfindungsraten 50–80%).
Identification and quantitation of methylcellulose amongst other thickeners in foods
Summary An analytical method is described for the isolation, identification and quantitative determination of methylcellulose in foods. First, natural thickeners and gums are precipitated with ethanol and can be analysed subsequently in a separate way. Depending on the composition of the food commodity in question, proteins, fats, and residual starch are removed and methylcellulose is isolated by precipitation with tannic acid or by gel permeation chromatography. Hydrolysis with hydrochloric acid is followed by separation of the methylglucoses formed by glass capillary gas chromatography as trimethylsilyloximes. From the sum of the components, the methylcellulose content and the degree of methylation can be calculated. The limit of determination in fortified samples was about 0.02 g/100 g for dairy products and as low as 0.005 g/100 g for fruit products, wine and beer (recoveries 50%–80%).相似文献
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Henning?M.?Beier Martin?Bujard Klaus?Diedrich Horst?Dreier Helmut?Frister Heribert?Kentenich Hartmut?Kre? Jan-Steffen?Krüssel Annika?K.?Ludwig Eva?Schumann Thomas?Strowitzki Jochen?Taupitz Christian?J.?Thaler Petra?Thorn Claudia?WiesemannEmail author Hans-Peter?Zenner 《Ethik in der Medizin》2018,30(2):153-158
87.
High-frequency electromagnetic dynamics properties of THP1 cells using scanning microwave microscopy
Oh YJ Huber HP Hochleitner M Duman M Bozna B Kastner M Kienberger F Hinterdorfer P 《Ultramicroscopy》2011,111(11):1625-1629
Microwave measurements combined with scanning probe microscopy is a novel tool to explore high-localized mechanical and electrical properties of biological species. Complex permittivities and permeabilities are detected through slight variations of an incident microwave signal. Here we report the high-frequency dependence of the electromagnetic dynamic characteristics in human monocytic leukemia cells (THP1) through local measurements by scanning microwave microscopy (SMM). The amplitude and phase images were shown to depend on the applied resonance frequency. While the amplitude yields information about the resistivity determined by the water and the ionic strength, the phase information reflects the dielectric losses arising from the fluid density. 相似文献
88.
Mikkelsen Lars Møller Madsen Tatiana Kozlova Schwefel Hans-Peter 《Wireless Personal Communications》2020,110(3):1551-1566
Wireless Personal Communications - Systems within IoT domains such as ITS, Smart City, Smart Grid and other, often rely on real-time information and communication. These types of systems often... 相似文献
89.
Matthias Laska Stefanie Kohlmann Hans-Peter Scheuber Laura Teresa Hernandez Salazar Ernesto Rodriguez Luna 《Journal of chemical ecology》2001,27(10):1997-2011
The taste responsiveness of six squirrel monkeys, five pigtail macaques, four olive baboons, and four spider monkeys to polycose, a starch-derived polysaccharide, was assessed in two-bottle preference tests of brief duration (2 min). In experiment 1, the monkeys were given the choice between tap water and defined concentrations of polycose dissolved in tap water. In experiment 2, the animals were given the choice between polycose and sucrose, fructose, glucose, lactose, and maltose presented in equimolar concentrations of 100 and 200 mM, respectively. The animals were found to prefer concentrations of polycose as low as 10 mM (pigtail macaques), 30 mM (olive baboons and spider monkeys), and 60 mM (squirrel monkeys) over tap water. Relative taste preferences were stable across the concentrations tested and indicate an order of relative effectiveness (sucrose > polycose maltose) in squirrel monkeys, spider monkeys, and olive baboons that is similar to the order of relative sweetness in humans. Pigtail macaques, however, displayed an order of relative effectiveness (maltose > polycose sucrose) that differs markedly from that found in the other primate species tested and is similar to relative taste preferences found in rodents such as rats. Both the high sensitivity of the pigtail macaques to polycose and their vivid predilection for this polysaccharide and its disaccharide constituent maltose suggest that Macaca nemestrina, unlike other primates, but like rodents, may have specialized taste receptors for starch. 相似文献
90.
Schreiber JV Frackenpohl J Moser F Fleischmann T Kohler HP Seebach D 《Chembiochem : a European journal of chemical biology》2002,3(5):424-432
A consortium of microorganisms was established that was able to grow with the beta-tripeptide H-beta-HVal-beta-HAla-beta-HLeu-OH, with the beta-dipeptide H-beta-HAla-beta-HLeu-OH, and with the beta-amino acids H-beta-HAla-OH, H-beta-HVal-OH, and H-beta-HLeu-OH as the sole carbon and energy sources. This growth was achieved after several incubation-transfer cycles with the beta-tripeptide as the substrate. During degradation of the beta-tripeptide H-beta-HVal-beta-HAla-beta-HLeu-OH, the temporary formation of a metabolite was observed. The metabolite was identified as the beta-dipeptide H-beta-HAla-beta-HLeu-OH by nuclear magnetic resonance spectroscopy and mass spectrometry. This result indicates that in the course of the degradation of the beta-tripeptide, the N-terminal beta-HVal residue was cleaved off by a not yet known mechanism. During the subsequent degradation of the beta-dipeptide, formation of additional metabolites could not be detected. The growth-yield coefficients Y(x/s) for growth on the beta-di- and beta-tripeptide both had a value of 0.45. When a 1:1 mixture of the beta-tripeptide and the corresponding alpha-tripeptide H-Val-Ala-Leu-OH was added to the enrichment culture, the alpha-peptide was completely utilized in six days and thereafter growth of the culture stopped. This result indicates that even in beta-peptide enrichment cultures, alpha-peptides are the preferred substrates. Our experiments clearly show for the first time that beta-peptides and beta-amino acids are amenable to biodegradation and that a microbial consortium was able to utilize these compounds as sole carbon and energy sources. Furthermore, the preparation of beta-amino acids, of derivatives thereof, and of beta-di- and beta-tripeptides is described. 相似文献