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101.
We review high-performance liquid chromatography (HPLC) methods for the determination of two major statins used in clinical treatment – simvastatin and atorvastatin – in various fields of application, including bio-analytical assays, pharmaceutical assays and environmental applications.
Statin molecules are known to be susceptible to interconversion of the lactone and acidic forms, so it is necessary to consider this phenomenon during method development. We highlight liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) methods, as they have become a method of choice in bio-analytical and environmental applications. We compare the methods from the point of view of sensitivity. We discuss selection of the precursor ion for performing selected reaction monitoring (SRM) in MS detection and sample preparation. 相似文献
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103.
Babić Sandra Horvat Alka J. M. Mutavdžić Dragana Čavić Dalibor Kaštelan-Macan Marija 《平面色谱法杂志一现代薄层色谱法》2007,20(2):95-99
JPC – Journal of Planar Chromatography – Modern TLC - Optimization of microwave-assisted extraction (MAE) as a method of sample preparation in thin-layer chromatographic (TLC) analysis... 相似文献
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107.
Decomposition of complete graphs into (0, 2)-prisms 总被引:1,自引:0,他引:1
R. Frucht and J.Gallian (1988) proved that bipartite prisms of order 2n have an α-labeling, thus they decompose the complete graph K 6nx+1 for any positive integer x. We use a technique called the ? +-labeling introduced by S. I. El-Zanati, C. Vanden Eynden, and N. Punnim (2001) to show that also some other families of 3-regular bipartite graphs of order 2n called generalized prisms decompose the complete graph K 6nx+1 for any positive integer x. 相似文献
108.
Alexander M. Macmillan Dalibor Panek Colin D. McGuinness John C. Pickup Duncan Graham W. Ewen Smith David J. S. Birch Jan Karolin 《Journal of Sol-Gel Science and Technology》2009,49(3):380-384
By using the fluorescent dye 6-propionyl-2-(N,N-dimethylamino) naphthalene (PRODAN) to monitor methanol generated during tetramethyl orthosilicate polymerization we have
optimised the encapsulation of protein in silica sol–gel monoliths with respect to completion of hydrolysis and distillation
in order to remove methanol such that protein can be added without denaturation. A minimum of 24 h at +4 °C was found to be
required before hydrolysis is complete and 3–5 min of vacuum distillation at 50 °C and 300 mbar needed to remove methanol
before the gel is formed. The biocompatibility of a tetramethyl orthosilicate sol–gel monolith was demonstrated by preserving
the trimer protein allophycocyanin (APC) in its native form for up to 500 h. This obviates the previously essential requirement
of covalently binding the trimer together in order to prevent dissociation into monomers and has enabled observation of native
APC trimer in a sol–gel pore for the first time down to the single molecule level using combined fluorescence spectroscopy
and confocal microscopy. The higher stability afforded by the protocol we describe could impact on the application of sol–gel
materials to single-molecule studies of wider bearing such as protein folding and aggregation. 相似文献
109.
Jurica Bauer Dalibor Mili Marina Modri 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(10):o512-o516
Ethyl 1‐ethyl‐6‐iodo‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylate, C14H14INO3, (I), and ethyl 1‐cyclopropyl‐6‐iodo‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylate, C15H14INO3, (II), have isomorphous crystal structures, while ethyl 1‐dimethylamino‐6‐iodo‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylate, C14H15IN2O3, (III), possesses a different solid‐state supramolecular architecture. In all three structures, O...I halogen‐bonding interactions connect the quinolone molecules into infinite chains parallel to the unique crystallographic b axis. In (I) and (II), these molecular chains are arranged in (101) layers, viaπ–π stacking and C—H...π interactions, and these layers are then interlinked by C—H...O interactions. The structural fragments involved in the C—H...O interactions differ between (I) and (II), accounting for the observed difference in planarity of the quinolone moieties in the two isomorphous structures. In (III), C—H...O and C—H...π interactions form (100) molecular layers, which are crosslinked by O...I and C—H...I interactions. 相似文献
110.
The classical framework for studying the equations governing the motion of lumped parameter systems presumes one can provide
expressions for the forces in terms of kinematical quantities for the individual constituents. This is not possible for a
very large class of problems where one can only provide implicit relations between the forces and the kinematical quantities.
In certain special cases, one can provide non-invertible expressions for a kinematical quantity in terms of the force, which
then reduces the problem to a system of differential-algebraic equations. 相似文献