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J. Großfeld A. Simmer J. van Loon W. Springer S. Juschkewitsch V. Kubelka J. Wagner S. Zuravlev Thompsonwerke W. Normann H. P. Trevithik M. F. Lauro A. Bömer A. Gehrke G. de Belsunce J. I. Lurje F. Fritz Zitek R. Otto A. Halter J. M. Purdy W. G. France W. L. Evans H. P. Kaufmann M. Keller 《Analytical and bioanalytical chemistry》1931,83(5-6):223-230
66.
R. Springer und H. Isak 《Fresenius' Journal of Analytical Chemistry》1964,199(5):363-366
Zusammenfassung Polyäthylenglykole vermögen die Existenz von Chromperoxid zu stabilisieren. Dabei wird die Oktettlücke des in freiem Zustande äußerst unbeständigen CrO5 durch das freie Elektronenpaar der Äthersauerstoffatome der Polyäthylenglykole besetzt. Auf dieser Stabilisierung des tiefblauen CrO5 basiert der hier beschriebene Nachweis der Polyäthylenglykole.
9. Mitteilung: Springer, R., u. H. Isak: Dtsch. Apotheker-Ztg. 103, 525 (1963). 相似文献
Summary Polyethylene glycols have the ability to stabilize chromium peroxide. The octet gap of CrO5 (which is extremely unstable in the free state) is filled up by the free electron pair of the ether oxygen atoms of the polyethylene glycols. The described detection of polyethylene glycols is based on this stabilisation of the dark blue CrO5.
9. Mitteilung: Springer, R., u. H. Isak: Dtsch. Apotheker-Ztg. 103, 525 (1963). 相似文献
67.
Loew M Springer R Scolari S Altenbrunn F Seitz O Liebscher J Huster D Herrmann A Arbuzova A 《Journal of the American Chemical Society》2010,132(45):16066-16072
Lipid domains in mammalian plasma membranes serve as platforms for specific recruitment or separation of proteins involved in various functions. Here, we have applied this natural strategy of lateral separation to functionalize lipid membranes at micrometer scale in a switchable and reversible manner. Membrane-anchored peptide nucleic acid and DNA, differing in their lipophilic moieties, partition into different lipid domains in model and biological membranes. Separation was visualized by hybridization with the respective complementary fluorescently labeled DNA strands. Upon heating, domains vanished, and both lipophilic nucleic acid structures intermixed with each other. Reformation of the lipid domains by cooling led again to separation of membrane-anchored nucleic acids. By linking appropriate structures/functions to complementary strands, this approach offers a reversible tool for triggering interactions among the structures and for the arrangement of reactions and signaling cascades on biomimetic surfaces. 相似文献
68.
The permeability of styrene-butadiene block copolymer foils with different composition prepared by casting and pressing has been investigated for the gases Ar, CO2, and CH4 at pressure difference of 400 mbar and at the temperature range 298 T [K] 333.The permeation process can be described by the solution diffusion mechanism. The diffusion coefficients decrease in the sequence of the gases Ar, CO2, and CH4 and the solubility coefficients increase in the sequence Ar, CH4, CO2.The dependence of the permeability on the composition of the block copolymer can be interpreted by the help of percolation theory and the effective medium theory. It follows the critical volume fraction of the percolation of the transport phase
PB
c
(= 0,23) and the coordination numberz (= 4) giving an information concerning the multiphase structure of the block copolymer.Presented in part at the 33rd Annual Meeting of the Colloid-Gesellschaft, Graz, Austria, September 14–16, 1987. 相似文献
69.
Tobias Becherer Denys Meshcheryakov Andreas Springer Volker Böhmer Christoph A. Schalley 《Journal of mass spectrometry : JMS》2009,44(9):1338-1347
Two series, one of tris‐urea macrocycles and another of hexakis‐urea macrocycles, are examined by (tandem) Fourier‐transform ion cyclotron resonance (FTICR) mass spectrometry with respect to their fragmentation patterns and anion binding properties. All macrocycles are based on two different building blocks, one of which is a very rigid xanthene unit and the other one is a more flexible diphenyl ether. The composition and the sequence of these units thus determine their flexibility. During the fragmentation of deprotonated oligourea macrocycles in the gas phase, one urea N? CO bond is cleaved followed by a scrambling reaction within the macrocycle structure. Consequently, fragments are observed that deviate from those that would be expected from the sequence of the subunits. Interesting anion binding properties involve the simultaneous recognition of two chloride anions by one of the hexakis‐urea macrocycles, whose flexibility allows this host to form a double‐helical structure. Flexibility also determines which of the hexameric receptors bears a high sulfate affinity. The interaction energy between some of the macrocycles and sulfate is high enough to even stabilize the intrinsically unstable sulfate dianion. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
70.
G. Scherowsky U. Müller J. Springer W. Trapp A. M. Levelut P. Davidson 《Liquid crystals》2013,40(4):1297-1306
The synthesis and mesomorphic properties of two liquid-crystalline side chain polymers with a chiral centre in the α or β position of the α-hydroxy acid representing the spacer unit are described. The chiral α branching leads to a dramatic decrease in the transition temperatures and a strong narrowing of the smectic mesophase (compared with the unbranched model compound I). The chiral β branching results in a chiral smectic phase, a pronounced contraction of the Sc phase, and the loss of the higher ordered Sf phase. The S*c phase was confirmed by X-ray investigations of oriented samples. Depending on the polymerization conditions samples were obtained which were oriented in melt drawn fibres either with their smectic layers or their mesogenic units in the direction of stress. 相似文献