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371.
The critical current lc of Nb3Sn conductors containing 1615 or 3721 filaments was measured in magnetic flux densities up to 18 T. The magnetic field was generated by a Bitter magnet. The overall current density of the conductor was at 10 T and 5 × 103 A cm?2 at 18 T. Values of up to 21.6 T were obtained for the upper critical flux density Bc2. The influence of the diffusion conditions upon lc, Bc2 and the superconducting transition temperature Tc have been related to the fraction of the total conductor cross-section taken up by Nb3Sn. This fraction serves as a rough measure of the pressure exerted upon the Nb3Sn within the conductor. 相似文献
372.
Anderson R. Springer L. Bricks B. Karras T. 《Quantum Electronics, IEEE Journal of》1975,11(4):172-174
A simple, reliable copper vapor laser is described with vapor produced by discharge heating. Average output power of 1.3 W has resulted at 6.8 kHz and a specific energy of 39 μJ/cm3. Copper vapor density as high as3 times 10^{16} cm-3was achieved. 相似文献
373.
R. Radtke R. Springer und W. Mohr 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1966,128(6):321-333
Zusammenfassung Zum Studium der Aromabestandteile aus frischem und gelagertem Röstkaffee werden von den drei Fraktionen verschiedener Siedebereiche die Verbindungen mittlerer Flüchtigkeit näher untersucht. Es handelt sich um ein. Vielkomponentengemisch (Sdp 100 bis etwa 220° C), das durch Trägerdampfdestillation unter vermindertem Druck gewonnen wird.Während die leichtflüchtigen Verbindungen (0–100° C) lediglich die Aromaspitze bedingen, erweisen sich die mittel- bis schwerflüchtigen Substanzen als die Träger des typischen Kaffee-Aromas, zu dem die Carbonyle zusammen mit den Phenolen mehr beitragen als das häufig für überaus bedeutsam gehaltene Furfurylmercaptan. Die Ergebnisse der chemischen Aufarbeitung lassen eindeutig erkennen, daß das volle Aroma des Kaffees nicht auf der Anwesenheit einzelner markanter Komponenten beruht, sondern durch Mischung einer Vielzahl von Verbindungen verschiedener Konstitution, Konzentration und Flüchtigkeit zustande kommt. Nur zusammen ergeben sie diese Wirkung, indem sich ihre Duft- und Geschmacksnuancen addieren, überlagern und gegenseitig abrunden. Hierbei sind vier Verbindungsklassen, nämlich Monocarbonsäuren, Stickstoffbasen, Phenole und neutrale Verbindungen, in erster Linie Vertreter der Carbonylreihe, von besonderer Bedeutung.Bei der Analyse der Aromakondensategelagerten Kaffees kann innerhalb der gaschromatographisch nachweisbaren Verbindungen bis etwa 170° C keine zusätzliche, möglicherweise den Altgeschmack verursachende Komponente nachgewiesen werden. Die Untersuchungsergebnisse deuten vielmehr darauf hin, daß man ebensowenig wie beim Frischaroma für den Altgeschmack eine eng begrenzte Anzahl von Verbindungen verantwortlich machen kann.I. Mitteilung: Diese Z.119, 293 (1963). Beide Mitteilungen sind Auszüge aus der Dissertation vonRosemarie Radtke, Universität München 1964. 相似文献
374.
Forschung im Ingenieurwesen - Auf der Basis des Ritz-Galerkinschen Verfahrens wird eine analytische Näherungsmethode zur Lösung der Reynoldsschen Differentialgleichung angegeben. Die... 相似文献
375.
376.
JM Casasnovas T Stehle JH Liu JH Wang TA Springer 《Canadian Metallurgical Quarterly》1998,95(8):4134-4139
The 3.0-A structure of a 190-residue fragment of intercellular adhesion molecule-1 (ICAM-1, CD54) reveals two tandem Ig-superfamily (IgSF) domains. Each of two independent molecules dimerizes identically with a symmetry-related molecule over a hydrophobic interface on the BED sheet of domain 1, in agreement with dimerization of ICAM-1 on the cell surface. The residues that bind to the integrin LFA-1 are well oriented for bivalent binding in the dimer, with the critical Glu-34 residues pointing away from each other on the periphery. Residues that bind to rhinovirus are in the flexible BC and FG loops at the tip of domain 1, and these and the upper half of domain 1 are well exposed in the dimer for docking to virus. By contrast, a residue important for binding to Plasmodium falciparum-infected erythrocytes is in the dimer interface. The presence of A' strands in both domains 1 and 2, conserved hydrogen bonds at domain junctions, and elaborate hydrogen bond networks around the key integrin binding residues in domain 1 make these domains suited to resist tensile forces during adhesive interactions. A subdivision of the intermediate (I) set of IgSF domains is proposed in which domain 1 of ICAM-1 and previously described I set domains belong to the I1 set and domain 2 of ICAM-1, ICAM-2, and vascular cell adhesion molecule-1 belong to the I2 set. 相似文献
377.
T. Gessner K. Gottfried R. Hoffmann C. Kaufmann U. Weiss E. Charetdinov P. Hauptmann R. Lucklum B. Zimmermann U. Dietel G. Springer M. Vogel 《Microsystem Technologies》2000,6(5):169-174
The present study is focused on the development of a gas sensor for application in a high temperature environment. The sensor
has been realised using thin films prepared on silicon substrates including a high temperature stable heating and wiring system.
TiO2 acts as sensitive layer. Measurements have been carried out in synthetic gas mixtures as well as in gases in a given application.
Neural networks and multivariate data analysis have been used for determining the gas concentrations. The capability to detect
CO, NO
x
, and toluene is shown.
Received: 3 February 2000/Accepted: 3 February 2000 相似文献
378.
J Kitayama MW Carr SJ Roth J Buccola TA Springer 《Canadian Metallurgical Quarterly》1997,158(5):2340-2349
At inflammatory sites in vivo, leukocytes may confront multiple, competing chemoattractive signals. We found significant differences between eosinophils and neutrophils in transendothelial chemotaxis to a chemoattractant diffusing from the lower chamber, when a chemoattractant that binds to another receptor is present at uniform concentration. The transendothelial migration of eosinophils to FMLP, C5a, RANTES, or MCP-3 was totally inhibited by the presence of the homologous chemoattractant, and only RANTES and MCP-3 showed mutual inhibition. C5a and to a lesser extent FMLP chemokinetically stimulated migration to RANTES and MCP-3, without stimulating random migration. Results with neutrophils contrasted. The presence of FMLP not only abrogated neutrophil transmigration to FMLP but also strongly decreased chemotaxis to C5a, IL-8, and Gro-alpha. Similarly, C5a inhibited neutrophil chemotaxis to IL-8 and Gro-alpha. IL-8 almost totally abrogated chemotaxis to Gro-alpha, but Gro-alpha only moderately inhibited chemotaxis to IL-8. Neither IL-8 nor Gro-alpha significantly inhibited transmigration to FMLP or C5a. Actin polymerization in eosinophils and neutrophils was desensitized by the same combinations of chemoattractants that desensitized chemotaxis. We conclude that eosinophils have at least three noninterfering receptor-signal transduction pathways for chemotaxis and actin polymerization. In contrast, the signaling pathways for FMLP, C5a, and IL-8/Gro-alpha in neutrophils are heterologously cross-desensitized, with a hierarchy of resistance to competing signals of FMLP > C5a > IL-8 > Gro-alpha, in agreement with previous results in neutrophils on the Ca2+-mobilizing response. These results may have important implications for the behavior of these cell types in inflammatory sites. 相似文献
379.
Andrew A. Efanov Christian G. Diskus Andreas Stelzer Hartwig W. Thim Kurt Lübke Andreas L. Springer 《电信纪事》1997,52(3-4):219-223
Two different 35 GHz low-cost rf front-end Doppler units suited for automotive applications have been constructed. The homodyne unit consists of both receiving and transmitting corporate-fed microstrip patch array antennas, a microstrip directional coupler, a monolithic GaAs fected oscillator and an integrated single Schottky diode mixer. The autodyne configuration uses only one antenna and the fected as a self-oscillating mixer. Inexpensive microstrip technology has been used which yields a good compromise between cost factor and technical performance. 相似文献
380.