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21.
Gowen AA Marini F Esquerre C O'Donnell C Downey G Burger J 《Analytica chimica acta》2011,705(1-2):272-282
Hyperspectral chemical imaging (HCI) integrates imaging and spectroscopy resulting in three-dimensional data structures, hypercubes, with two spatial and one wavelength dimension. Each spatial image pixel in a hypercube contains a spectrum with >100 datapoints. While HCI facilitates enhanced monitoring of multi-component systems; time series HCI offers the possibility of a more comprehensive understanding of the dynamics of such systems and processes. This implies a need for modeling strategies that can cope with the large multivariate data structures generated in time series HCI experiments. The challenges posed by such data include dimensionality reduction, temporal morphological variation of samples and instrumental drift. This article presents potential solutions to these challenges, including multiway analysis, object tracking, multivariate curve resolution and non-linear regression. Several real world examples of time series HCI data are presented to illustrate the proposed solutions. 相似文献
22.
The properties of the negative parity states of55Fe and57Fe are investigated in the framework of the intermediate coupling model. In the model, a neutron or a quasineutron is coupled to anharmonic vibrations of the core. Anharmonicities of the vibrations are estimated through the observed properties of the core. Energy levels, spectroscopic factors and electromagnetic properties have been calculated. The results of the present calculations are also compared with available experimental results and other theoretical results. The model reasonably accounts for many of the properties of the low-lying states. 相似文献
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A method is presented for evaluating management programmes in which the dischargers are divided into groups. Analogous non-linear mathematical formulations are presented for direct regulation and effluent charge programmes, and a non-linear branch-and-bound solution procedure is described. A detailed algorithm is described for the effluent charge case; it is shown to be very practical in an application to data for the Delaware estuary. 相似文献
25.
Nuclear spin-lattice relaxation-time measurements of 51V in A-15-phase V0.75-xGa0.25+x have been made in both well-annealed and neutron-irradiated samples. A tight-binding analysis of the results indicates a strong correlation of Tc with the density of states at the Fermi level in the δ-subbands. 相似文献
26.
We extend the Shoenfield jump inversion theorem to the members of any class with nonzero measure; i.e., for every set , there is a real such that . In particular, we get jump inversion for -random reals.
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C. Wade Downey Grant J. Dixon Jared A. Ingersoll Claire N. Fuller Kenneth W. MacCormac Anna Takashima Rohina Sediqui 《Tetrahedron letters》2019,60(44):151192
Trimethylsilyl trifluoromethanesulfonate (TMSOTf) and a trialkylamine base promote both in situ enol silane/silyl ketene acetal formation and Mukaiyama aldol addition reactions between a variety of reaction partners in a single reaction flask. Isolation of the required enol silane or silyl ketene acetal is not necessary. For example, crossed aldol reactions between α-disubstituted aldehydes and non-enolizable aldehydes yield β-hydroxy aldehydes in good yield. In a related reaction, the common laboratory solvent ethyl acetate functions as both an enolate precursor and a green reaction solvent. When thioesters are employed as enolate precursors, high yields for additions to non-enolizable aldehydes are routinely observed. 相似文献
29.
C. Wade Downey Sarah E. CovingtonDerek C. Obenschain Evan HallidayJames T. Rague Danielle N. Confair 《Tetrahedron letters》2014
para-Methoxybenzyl methyl ether acts as an alkylating agent for thiols in the presence of trimethylsilyl trifluoromethanesulfonate and trialkylamine base in good yields (58–96%). Aryl ketones are alkylated under similar conditions, probably through an enol silane intermediate, also in high yields (67–95%). The active alkylating species is likely a p-methoxybenzyl cation. 相似文献
30.
A limitation of large-scale viticultural trials is the time and cost of comprehensive compositional analysis of the fruit by high-performance liquid chromatography (HPLC). In addition, separate methods have generally been required to identify and quantify different classes of metabolites. To address these shortcomings a reversed-phase HPLC method was developed to simultaneously separate the anthocyanins and flavonols present in grape skins. The method employs a methanol and water gradient acidified with 10% formic acid with a run-time of 48 min including re-equilibration. Identity of anthocyanins and flavonols in Shiraz (Vitis vinifera L.) skin was confirmed by mass spectral analysis. 相似文献