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Günther Vitzthum Ekkehard Lindner 《Angewandte Chemie (International ed. in English)》1971,10(5):315-326
Sulfinatometal complexes exhibit unusual features in their structure, preparation, and use, and have attracted rapidly growing interest. Their structures are determined by the ability of the RSO group both to act as a monodentate ligand (sulfinato-S or sulfinato-O) and to add to coordination centers as a bidentate ligand, either intramolecularly or intermolecularly, via the two oxygens atoms (sulfinato-O,O′) or via the sulfur atom and one of the oxygens (sulfinato-O,S). 相似文献
85.
We demonstrate a dynamical origin for the dimension-five seesaw operator in dimensional deconstruction models. Light neutrino masses arise from the seesaw scale which corresponds to the inverse lattice spacing. It is shown that the deconstructing limit naturally prefers maximal leptonic mixing. Higher-order corrections which are allowed by gauge invariance can transform the bimaximal into a bilarge mixing. These terms may appear to be nonrenormalizable at scales smaller than the deconstruction scale. 相似文献
86.
A general labelling method is presented which allows the determination of the number of guanidine groups (related to arginine and homoarginine in peptides and proteins) by means of mass spectrometry. It implies a guanidine-selective derivatization step with 2,3-butanedione and an arylboronic acid under aqueous, alkaline conditions (pH 8-10). The reaction mixture is then directly analysed by electrospray ionization mass spectrometry without further sample pretreatment. Other amino acids are not affected by this reaction although it is demonstrated that lysine side-chains may be unambiguously identified when they are converted to homoarginine prior to derivatization. Guanidine functionalities, as e.g. in the amino acid arginine, are easily identified by the characteristic mass shift between underivatized and derivatized analyte. The tagging procedure is straightforward and selective for guanidine groups. The influence of several experimental parameters, especially the pH of the solution and the choice of reagents, is examined and the method is applied to various arginine-containing peptides and to lysozyme as a representative protein. Possible applications of this technique and its limitations are discussed. 相似文献
87.
Lindner R 《Electrophoresis》2001,22(3):386-393
Many different methods for the fractionation of subcellular organelles have been reported. However, no protocol for rapid separation of plasma membrane, Golgi/trans-Golgi network (TGN) and endosomes is available to date. Such a method is a prerequisite for a quantitative biochemical analysis of vesicular transport from the Golgi/TGN compartment to plasma membrane and endosomes. Here a density gradient electrophoresis protocol is described that allows the fractionation of these organelles in one step. This protocol requires only low-cost instrumentation available in most biochemical laboratories. 相似文献
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Abstract The knowledge of water exchange reaction mechanism in aqueous solutions of Gd3+ polyaminocarboxylates is important for the understanding of the relatively slow water exchange rates measured for these complexes. Variable ressure measurements show a change of mechanism from associatively activated on [Gd(H2O)8]3+ and [Gd(PDTA)(H2O2)2]? to probably limiting dissociative on the MRI contrast agents [Gd(DOTA)(H2O)]?, [Gd(DTPA)(H2O)]2? and [Gd(DTPA-BMA)(H2O)]. 相似文献
90.
Ahmed AY Oekermann T Lindner P Bahnemann D 《Physical chemistry chemical physics : PCCP》2012,14(8):2774-2783
The photooxidation of methanol as a model substance for pollutants on rutile TiO(2) (001) and (100) surfaces was investigated using intensity modulated photocurrent spectroscopy (IMPS). The results are analyzed in view of the influence of the surface structure, the methanol concentration and the electrode potential on the rate constants of charge transfer and recombination. The obtained results have been explained with a model combining the theory of IMPS for a bulk semiconductor surface and the nature of the surface-bound intermediates (alternatively mobile or immobile OH˙ radicals). The results indicate that water photooxidation proceeds via mobile OH˙ radicals on both surfaces, while methanol addition gives rise to the involvement of immobile OH˙ radicals on the (100) surface. Detailed analysis in view of the surface structures suggests that the latter observation is due to efficient electron transfer from bridging OH˙ radicals on the (100) surface to methanol, while coupling of two of these radicals occurs in the absence of methanol, making them appear as mobile OH˙ radicals. In the case of the (001) surface, the coupling reaction dominates even in the presence of methanol due to the smaller distance between the bridging OH˙ radicals, leading to more efficient water oxidation, but less efficient methanol photooxidation on this surface. 相似文献