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Céline Degrande Nicolas Greiner Wolfgang Kilian Olivier Mattelaer Harrison Mebane Tim Stelzer Scott Willenbrock Cen Zhang 《Annals of Physics》2013
We advocate an effective field theory approach to anomalous couplings. The effective field theory approach is the natural way to extend the standard model such that the gauge symmetries are respected. It is general enough to capture any physics beyond the standard model, yet also provides guidance as to the most likely place to see the effects of new physics. The effective field theory approach also clarifies that one need not be concerned with the violation of unitarity in scattering processes at high energy. We apply these ideas to pair production of electroweak vector bosons. 相似文献
23.
Manfred Stelzer 《Mathematische Zeitschrift》2007,257(1):81-106
Relations between category and strong category are studied. The notion of a homotopy coalgebra of order r over the Ganea comonad
is introduced. It is shown that cat(X) =Cat(X) holds if a finite 1-connected complex X carries such a structure with r sufficiently large. 相似文献
24.
Attrition of crystals in industrial crystallization is the major source of secondary nucleation and has strong effects on product quality. This work describes attrition in industrial crystallizers using an empirical engineering model based on dimensionless groups describing crystal properties, suspension properties, and crystallizer geometry and operating conditions. Here the attrition rate of sodium chloride crystals in a small scale mixed‐suspension crystallizer is studied, varying the following parameters: impeller speed, parent crystal size, suspension density, draft‐tube impeller clearance, off‐bottom impeller clearance, impeller type, and impeller material. It was found that the attrition rate depends on most of the variables investigated. The direction of the dependence is predictable based on intuitive modeling. An empirical power law model based on dimensionless groups predicted by Buckingham‐Pi theory (using variables mentioned above) gives a good fit to the data. 相似文献
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Ohne Zusammenfassung 相似文献
28.
Kappaun S Sović T Stelzer F Pogantsch A Zojer E Slugovc C 《Organic & biomolecular chemistry》2006,4(8):1503-1511
Three 5,7-pi-extended 8-benzyloxyquinolines, namely 5,7-diphenyl-, 5,7-bis(biphenyl-4-yl)- and 5,7-bis(4-dibenzothiophenyl)-8-benzyloxyquinoline were prepared and investigated as fluorescent pH-probes in nonaqueous solution. Absorption and photoluminescence spectra of the introduced compounds also including the starting material 8-benzyloxy-5,7-dibromoquinoline as well as their N-protonated counterparts were recorded and the results were rationalized by quantum-chemical calculations. A pronounced red shift of the emission occurred upon protonation of the non halogenated derivatives, while the dibromo-derivative is hardly emissive and is virtually not protonated under the conditions used. The diphenyl- and the bis(biphenyl)-derivative especially show promising photoluminescence quantum yields both in the parent and the protonated state making them candidates for the active component in pH sensing applications. 相似文献
29.
Tim Hammerer Laurent Weisgerber Stefan Schenk Othmar Stelzer Ulli Englert Walter Leitner Giancarlo Franciò 《Tetrahedron: Asymmetry》2012,23(1):53-59
New diphosphinite ligands based on atropoisomeric diol backbones and (R,R)-2,5-dimethylphospholane moieties have been prepared and fully characterised. For each ligand structure, both diastereomers have been synthesised. These ligands are available through a straightforward procedure in good yields. The solid state structures of two diastereomeric ligands are reported. These ligands have been applied to Rh-catalysed asymmetric hydrogenations and hydroformylations of CC bonds as well as in Ir-catalysed asymmetric hydrogenations of CN bonds. Turnover frequencies in the range of 10,000 h?1 and enantioselectivities of up to 98% ee have been achieved. The different chirality elements within the ligands led to marked cooperative effect in catalysis. Interestingly, there is no general privileged diastereomeric structure but rather a matched diastereomer for each application. 相似文献
30.
Horst Schlick Franz Stelzer Günther Leising 《Monatshefte für Chemie / Chemical Monthly》2001,15(1):441-452
In this paper we report on the synthesis and characterization of a variety of poly-phenylenevinylene (PPV) derivatives containing para- and meta-linkages in the backbones. By the m-linkages the conjugation lengths of the oligo-m,p-phenylenevinylenes were limited, thus blueshifting the UV/Vis absorption and also the photoluminescence (PL) spectra. Alkoxy substituted oligo-m,p-phenylenevinylenes exhibited absorption and emission spectra at higher wavelengths than oligomers without oxygen directly attached to the backbone. Replacing p-phenylene by 4,4′-biphenylene moieties also led to a hypsochromic shift in the optical spectra. We chose the Heck coupling reaction to synthesize substituted oligomers consisting of alternating p-phenylenevinylene and m-phenylenevinylene units. They were characterized by 1H NMR, 13C NMR, FT IR, UV/VIS, and GPC analysis. 相似文献