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71.
Abstract

The corrosion resistance of Hastelloy C-276 and titanium alloy G5 against C1 anion which was generated by supercritical water oxidation (scWO) of 3-chlorobiphenyl (3-PCB) in a flow reactor was investigated over a period of 336 hours at a constant pressure of 30 MPa. The condition of the scWO reaction zone was fixed at 750 K. The concentration of chlorine in the effluent collected after cooling to ambient temperature was about 850 wppm. The Hastelloy C-276 has a nominal ratio of approximately 3.7 Ni/l Cr. The Ni/Cr ratio in the effluent was the same with the nominal ratio, and the Hastelloy C-276 was proved to be corroded on the surface located between the bottom of the reactor and the cooling parts, which are under sub- and near- critical conditions of water. The corrosion rate was found to be 5 to 34mm/y in the zone where the temperature ranged from 543 K to 650 K and the corrosion spread over the whole surface of the alloy; however, one can hardly observe such a serious corrosion except the zone located in the between the reactor and the cooling part.  相似文献   
72.
The content of α‐hydroxy acids and their enantiomers can be used to distinguish authentic and adulterated fruit juices. Here, we investigated the use of ligand exchange CE with two kinds of central metal ion in a BGE for the simultaneous determination of enantiomers of dl ‐malic, dl ‐tartaric and dl ‐isocitric acids, and citric acid. Ligand exchange CE with 100 mM d ‐quinic acid as a chiral selector ligand and 10 mM Cu(II) ion as a central metal ion could enantioseparate dl ‐tartaric acid but not dl ‐malic acid or dl ‐isocitric acid. Addition of 1.8 mM Sc(III) ion to the BGE with 10 mM Cu(II) ion to create a dual central metal ion system permitted the simultaneous determination of these α‐hydroxy acid enantiomers and citric acid. The proposed ligand exchange CE was thus well suited for detecting adulteration of fruit juices.  相似文献   
73.
This paper presents detailed numerical results of the competitive diffusion Lotka-Volterra equation (May-Leonard type). First, we derive the global phase diagrams of attractors in the parameter space including the system size, where transition lines between simple attractors are clearly obtained in accordance with the results of linear stability analysis, but the transition borders become complex when multi-basin structures appear. The complex aspects of the transition borders are studied in the case when the system size decreases. Next, we show the statistical aspects of the turbulence with special attention to the onset of the supercritical Hopf bifurcation. Several characteristic quantities, such as correlation length, correlation time, Lyapunov spectra and Lyapunov dimension, are investigated in detail near the onset of turbulence. Our data show the critical scaling law near the onset only in the restricted parameter domain. However even when the critical indices are not determined accurately, it is shown that the empirical scaling relations are obtained in a wide parameter domain far from the onset point and those scaling indices satisfy several relations. These scaling relations are discussed in comparison with the result derived by the phase reduction method. Lastly, we make a conjecture about the stability of an ecosystem based on the bifurcation diagram: the ecosystem obeying the Lotka-Volterra equation in the case of May-Leonard type is stabilized more as the system size increases.  相似文献   
74.
Undoped layered oxynitrides have not been considered as promising H2‐evolution photocatalysts because of the low chemical stability of oxynitrides in aqueous solution. Here, we demonstrate the synthesis of a new layered perovskite oxynitride, K2LaTa2O6N, as an exceptional example of a water‐tolerant photocatalyst for H2 evolution under visible light. The material underwent in‐situ H+/K+ exchange in aqueous solution while keeping its visible‐light‐absorption capability. Protonated K2LaTa2O6N, modified with an Ir cocatalyst, exhibited excellent catalytic activity toward H2 evolution in the presence of I? as an electron donor and under visible light; the activity was six times higher than Pt/ZrO2/TaON, one of the best‐performing oxynitride photocatalysts for H2 evolution. Overall water splitting was also achieved using the Ir‐loaded, protonated K2LaTa2O6N in combination with Cs‐modified Pt/WO3 as an O2 evolution photocatalyst in the presence of an I3?/I? shuttle redox couple.  相似文献   
75.
Photodissociation of trimethylaluminum [Al(CH3)3] adsorbed on a silica (SiO2) substrate at 110 K has been studied by multiphoton ionization time-of-flight mass spectrometry. Translational energy distributions of aluminum and AlCH3 fragments can be fitted with a composition of two Maxwell–Boltzmann distributions. The two components are attributed to different environments of photodissociating parent molecules in the multilayer.  相似文献   
76.
We demonstrate a novel waveform mesurement system of ultra-short optical pulses based on the two-photon absorption process in a Si-image sensor. Using an interferometer with a tilt mirror in the reference path, the relative time difference between the signal and reference pulses is spatially distributed on the Si-image sensor, so the intensity auto-correlation is monitored as an image at a time without using moving parts. This system can create or remove an interference fringe pattern overlapped on the auto-correlation image by controlling the polarization states of the laser pulse, which is useful for measuring the crossing angle between the signal and reference beams as well as avoiding contamination of the interference fringe into the auto-correlation image. We successfully measured optical pulses less than 100 fs from a fiber ring laser with a temporal resolution of 0.4 fs. The obtained waveform agreed well with that observed with a conventional second harmonic generation (SHG) based auto-correlator.  相似文献   
77.
Defocusing techniques for detecting metastable ions of rather complex molecules were investigated and a generalised procedure, which provides efficient methods in the analysis of fragmentation pathways of complex compounds, was established. Additionally, a new method to differentiate between the transition in the first and the third field free regions, was developed.  相似文献   
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