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61.
During preformulation studies of pharmaceutical solid dosage forms, thermal analysis techniques are very useful to detect
physical or chemical incompatibilities between the drug and adjuvants of interest that might interfere with efficacy and safety
of the final drug product. Differential scanning calorimetry (DSC) and thermogravimetry (TG) are useful tools for this purpose.
The aim of this study was to investigate the thermoanalytical behavior of olanzapine (OLZ) when mixed with several excipients
commonly used in solid dosage forms such as microcrystalline cellulose, croscarmellose, dicalcium phosphate dihydrate (DCPD),
lactose, magnesium stearate, and povidone. Following DSC and TG analyses, powder X-ray diffraction tests were carried out.
Thermoanalytical methods showed evidence of interaction between OLZ and magnesium stearate, lactose, and povidone. These results
can be useful during the selection of excipients for pharmaceutical formulation development. 相似文献
62.
Milan Randić Damir Vukičević Alexandru T. Balaban Marjan Vračko Dejan Plavšić 《Journal of computational chemistry》2012,33(11):1111-1122
We report on calculated CC bond currents for a dozen derivatives of hexabenzocoroenene in which one or more proximal carbon atoms at the molecular periphery have been bridged. The approach that we use is graph‐theoretical in nature, following our outline of this method in 2003, which is based on finding all conjugated circuits in all Kekulé valence structures of these molecules. To the π‐electrons having 4n + 2 π‐electrons are assigned anticlockwise π‐electron currents and to conjugated circuits having 4n π‐electrons are assigned π‐electron currents. One may summarize the results reported in this work by stating that CC bond currents in the compounds considered decrease on going from peripheral rings to the central ring of the molecule, and also that CC bond currents decrease by insertion of bridges to proximal peripheral benzenoid rings. © 2012 Wiley Periodicals, Inc. 相似文献
63.
Maja ?umar Ristovi? Maja Gruden Pavlovi? Matija Zlatar Vladimir Blagojevi? Katarina An?elkovi? Dejan Poleti Dragica M. Mini? 《Monatshefte für Chemie / Chemical Monthly》2012,107(3):1133-1139
Abstract
A Zn(II) complex with N-benzyloxycarbonylglycinato ligands was studied by non-isothermal methods, in particular Kissinger–Akahira–Sunose’s method, and further analysis of these results was performed by Vyazovkin’s algorithm and an artificial compensation effect. Density functional theory calculations of thermodynamic quantities were performed, and results obtained by both methods are consistent, thus clarifying the mechanism of this very interesting multi-step degradation. 相似文献64.
Colloidal interactions between proteins determine the behavior and stability of globular proteins such as monoclonal antibodies (mAbs) against their propensity to cluster formation in solution. We study interactions between these proteins through their dilute solution behavior. Experiments to quantify intermolecular interactions were done using Dynamic and Static Light Scattering (DLS and SLS) in a high-throughput manner in parallel with zeta potential measurements with Laser Doppler Electrophoresis method (M3-PALS). This approach offers a rapid indirect determination of colloidal interactions through their measured second virial coefficient. Electrostatic part of the DLVO interaction was conveniently parameterized via the corresponding surface charge and/or surface potential, while the van der Waals interactions were parameterized via their Hamaker coefficient, both as functions of ionic strength and pH of the bathing solution. This parametrization of protein-protein interactions improves our understanding of mAb assembly and provides a means for its control by solution parameter variation. Additionally, our results also provide a consistency check and validation of applicability of the DLVO theory in mAbs solution assembly processes. 相似文献
65.
66.
Slobodan M. Vuković Najdan B. Aleksić Dejan V. Timotijević Milivoj R. Belic 《Optics Communications》2012,285(6):1148-1154
We studied electromagnetic wave transmission through layered structures that include negative index materials. The excitation of leaky guided modes leads to the formation of anomalous lateral shifts in the reflected beam with a double-peak structure and in the transmitted beam with a single-peak structure. In the absence of losses, we demonstrate that the total transparency (i.e. zero reflection) of the slab waveguide with the negative index material can be achieved under conditions in which high reflectivity is normally expected. We demonstrate the trade-off effect between the high transmission and the high lateral shift. This peculiar effect exists not only for the pure TE or the pure TM polarization of the obliquely incident radiation, but also under certain circumstances for both of them simultaneously i.e. for the nonpolarized radiation. 相似文献
67.
We present a theoretical analysis of the image formation in structured illumination wide-field fluorescence microscopy (SIWFFM). We show that the optically sectioned images obtained with this approach possess the optical sectioning strengths comparable to those obtained with the confocal microscope. We further show that the transfer function behaviour is directly comparable to that of the true confocal instrument. The theoretical considerations are compared with and confirmed by experimental results. 相似文献
68.
69.
We put forward a novel index of molecular complexity, ξ, taking into account the symmetry of a molecular graph and the specificity of structural components considered. The ξ index is defined as the sum of augmented valences of all mutually nonequivalent vertices in a molecular graph. The augmented valence of a vertex in a graph is the sum of its valence and valences of all neighboring vertices with the weight 1/2d depending on their distance, d, from the vertex. The ξ index is examined on the set of octane isomers and some special classes of graphs. It is also compared with a certain number of alternative complexity measures considered in the literature. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003 相似文献
70.
Ljiljana Karanovi Dejan Poleti Jelena Rogan Goran A. Bogdanovi Anne Spasojevi‐de Bir 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(5):m275-m279
The title complexes, catena‐poly[[aqua(1,10‐phenanthroline‐κ2N,N′)cobalt(II)]‐μ‐benzene‐1,4‐dicarboxylato‐κ2O1:O4], [Co(C8H4O4)(C12H8N2)(H2O)], (I), and catena‐poly[[[(di‐2‐pyridyl‐κN‐amine)copper(II)]‐μ‐benzene‐1,4‐dicarboxylato‐κ4O1,O1′:O4,O4′] hydrate], [Cu(C8H4O4)(C10H9N3)]·H2O, (II), take the form of zigzag chains, with the 1,4‐benzenedicarboxylate ion acting as an amphimonodentate ligand in (I) and a bis‐bidentate ligand in (II). The CoII ion in (I) is five‐coordinate and has a distorted trigonal–bipyramidal geometry. The CuII ion in (II) is in a very distorted octahedral 4+2 environment, with the octahedron elongated along the trans O—Cu—O bonds and with a trans O—Cu—O angle of only 137.22 (8)°. 相似文献