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41.
The title compounds are synthesized from the elements (950—1000 °C, 45 min—48 h) and characterized by single crystal XRD and DFT electronic structure calculations. 相似文献
42.
Self-assembling mini cell-penetrating peptides enter by both direct translocation and glycosaminoglycan-dependent endocytosis 总被引:1,自引:0,他引:1
Bode SA Thévenin M Bechara C Sagan S Bregant S Lavielle S Chassaing G Burlina F 《Chemical communications (Cambridge, England)》2012,48(57):7179-7181
A small library of cell-penetrating peptides (CPPs) containing a minimized cationic domain and a lipophilic domain of different size was studied. CPPs that could self-assemble were found to enter cells more efficiently, triggering a glycosaminoglycan-dependent pathway. 相似文献
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44.
We consider liquid metal flow in a square duct with electrically insulating walls under the influence of a magnetic point dipole using three-dimensional direct numerical simulations with a finite-difference method. The dipole acts as a magnetic obstacle. The Lorentz force on the magnet is sensitive to the velocity distribution that is influenced by the magnetic field. The flow transformation by an inhomogeneous local magnetic field is essential for obtaining velocity information from the measured forces. In this paper we present a numerical simulation of a spatially developing flow in a duct with laminar inflow and periodic boundary conditions. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
45.
Rafael Almeida Menck Diógenes Saulo de Lima Saskia Carolina Seulin Vilma Leyton Carlos Augusto Pasqualucci Daniel Romero Muñoz Michael David Osselton Mauricio Yonamine 《Journal of separation science》2012,35(23):3361-3368
Here, we present a method for measuring barbiturates (butalbital, secobarbital, pentobarbital, and phenobarbital) in whole blood samples. To accomplish these measurements, analytes were extracted by means of hollow‐fiber liquid‐phase microextraction in the three‐phase mode. Hollow‐fiber pores were filled with decanol, and a solution of sodium hydroxide (pH 13) was introduced into the lumen of the fiber (acceptor phase). The fiber was submersed in the acidified blood sample, and the system was subjected to an ultrasonic bath. After a 5 min extraction, the acceptor phase was withdrawn from the fiber and dried under a nitrogen stream. The residue was reconstituted with ethyl acetate and trimethylanilinium hydroxide. An aliquot of 1.0 μL of this solution was injected into the gas chromatograph/mass spectrometer, with the derivatization reaction occurring in the hot injector port (flash methylation). The method proved to be simple and rapid, and only a small amount of organic solvent (decanol) was needed for extraction. The detection limit was 0.5 μg/mL for all the analyzed barbiturates. The calibration curves were linear over the specified range (1.0 to 10.0 μg/mL). This method was successfully applied to postmortem samples (heart blood and femoral blood) collected from three deceased persons previously exposed to barbiturates. 相似文献
46.
Saskia Wolf Dipl.‐Chem. Tanja Zismann Dipl.‐Chem. Nathalie Lunau Dipl.‐Chem. Chris Meier Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(31):7656-7664
A reliable and high yielding synthetic pathway for the synthesis of the biologically highly important class of nucleoside diphosphate sugars (NDP‐sugars) was developed by using various cycloSal‐nucleotides 1 and 9 as active ester building blocks. The reaction with anomerically pure pyranosyl‐1‐phosphates 2 led to the target NDP‐sugars 20 – 45 in a nucleophilic displacement reaction, which cleaves the cycloSal moiety in anomerically pure forms. As nucleosides cytidine, uridine, thymidine, adenosine, 2′‐deoxy‐guanosine and 2′,3′‐dideoxy‐2′,3′‐didehydrothymidine were used while the phosphates of D ‐glucose, D ‐galactose, D ‐mannose, D ‐NAc‐glucosamine, D ‐NAc‐galactosamine, D ‐fucose, L ‐fucose as well as 6‐deoxy‐D ‐gulose were introduced. 相似文献
47.
Xiaofei Chen Christian Mevissen Saskia Huda Christian Gb Iris M. Oppel Markus Albrecht 《Angewandte Chemie (International ed. in English)》2019,58(37):12879-12882
Two biscatecholester ligands with oligoether spacers were used to prepare dinuclear titanium(IV) triscatecholate based helicates. In the case of Li4[( 1 / 2 )3Ti2], “classical” helicates with three internally bound Li+ ions and syn‐oriented ligands in the complex units (fac/fac isomer) were obtained. In the case of the sodium salt Na4[( 2 )3Ti2], a different homochiral dinuclear triple‐stranded helicate with two internally bound Na+ ions was formed. The complex units are anti‐configured, and two of the ligand spacers are connecting internal with external positions of the helicate (mer/mer isomer). Removal of the sodium ions and addition of lithium ions leads to the switching from one topology to the other with an expanded helicate [( 2 )3Ti2]4? as an intermediate. Switching back to the “non‐classical” helicate cannot be observed because severe structural rearrangements would be required. 相似文献
48.
Yangming Lin Qing Lu Feihong Song Linhui Yu Anna K. Mechler Robert Schlgl Saskia Heumann 《Angewandte Chemie (International ed. in English)》2019,58(26):8917-8921
The abundance of available surface chemical information and edge structures of carbon materials have attracted tremendous interest in catalysis. For the oxygen evolution reaction (OER), the edge effects of carbon materials have rarely been studied in detail because of the complexity of various coexisting edge configurations and the controversy between carbon corrosion and carbon catalysis. Herein, the exact roles of common carbon active edge sites in the OER were interrogated using polycyclic aromatic hydrocarbons (PAHs) with designated configurations (zigzag and armchair) as model probe molecules, with a focus on structure–function relationships. Zigzag configurations of PAHs showed high activity for the OER while also showing a good stability at a reasonable potential. They show a TOF value of 0.276 s?1 in 0.1 m KOH. The catalytic activity of carbon edge sites was further effectively regulated by extending the π conjugation structure at a molecular level. 相似文献
49.
50.
Saskia Kind 《International Journal of Theoretical Physics》2008,47(12):3341-3390
Spinor relativity is a unified field theory, which derives gravitational and electromagnetic fields as well as a spinor field
from the geometry of an eight-dimensional complex and ‘chiral’ manifold. The structure of the theory is analogous to that
of general relativity: it is based on a metric with invariance group GL(ℂ2), which combines the Lorentz group with electromagnetic U(1), and the dynamics is determined by an action, which is an integral of a curvature scalar and does not contain coupling
constants. The theory is related to physics on spacetime by the assumption of a symmetry-breaking ground state such that a
four-dimensional submanifold with classical properties arises. In the vicinity of the ground state, the scale of which is
of Planck order, the equation system of spinor relativity reduces to the usual Einstein and Maxwell equations describing gravitational
and electromagnetic fields coupled to a Dirac spinor field, which satisfies a non-linear equation; an additional equation
relates the electromagnetic field to the polarization of the ground state condensate. 相似文献