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1.
Simen Gjelseth Antonsen Arne Joakim C. Bunkan Tomas Mikoviny Yngve Stenstrøm Armin Wisthaler 《Molecular physics》2020,118(15)
The kinetics of the O3, OH and NO3 radical reactions with diazomethane were studied in smog chamber experiments employing long-path FTIR and PTR-ToF-MS detection. The rate coefficients were determined to be k CH2NN+O3?=?(3.2?±?0.4)?×?10?17 and k CH2NN+OH?=?(1.68?±?0.12)?×?10?10 cm3 molecule?1 s?1 at 295?±?3?K and 1013?±?30 hPa, whereas the CH2NN?+?NO3 reaction was too fast to be determined in the static smog chamber experiments. Formaldehyde was the sole product observed in all the reactions. The experimental results are supported by CCSD(T*)-F12a/aug-cc-pVTZ//M062X/aug-cc-pVTZ calculations showing the reactions to proceed exclusively via addition to the carbon atom. The atmospheric fate of diazomethane is discussed. 相似文献
2.
A formula of Kotani for the coupling of equivalent particles in a field of a given symmetry is rederived using group algebraic methods. 相似文献
3.
A unitary group formulation of the many-electron problem is employed to give explicit representations of state vectors which are convenient for the discussion of progerties derived from propagatorcalculations. New results are obtained concerning the nature of various random-phase-like approximations and ground state representatives are generated from consistency requirements for the spectral resolution of the polarization propagator. The explicit solution admits the calculation of ground state average values for arbitrary operators and a variational upper bound to the ground state energy. 相似文献
4.
A translation is made of spin projection methods into the language of second quantization. This leads to a new formula for the Sanibel coefficients and expressions convenient to use for automatic calculation of spin projections. 相似文献
5.
An approximate electron propagator method for predictive calculations of molecular electron affinities is proposed. The self-energy accounts for relaxation effects to all orders Additional correlation effects are treated using a diagonal approximation with shifted denominators. Applications to CN, NH2, and PH2 are reported. 相似文献
6.
Li2SO4 as a model ionic conductor has received very much attention over several decades. Especially, in recent years Li2SO4 and Li2SO4-Al2O3 have been mentioned as promising proton conducting electrolytes for applications such as intermediate temperature fuel cells
and novel cogeneration systems regarding H2S handling devices. This has encouraged us to strive towards further improvement of the properties of the materials to meet
the demands of the applications.
In order to improve the properties of this system, a new process, a suspension technique, has been recently developed to prepare
nanostructured powder and thin film Li2SO4-Al2O3 membranes. The powders and thin films have a well crystallised structure composed of two phases, Li2SO4 and γ-Al2O3, and excellent mechanical strength. The thin film thickness is in the scale of a few to several mm with a smooth and shining
surface and a homogeneous macroscopic structure.
It is a very interesting phenomenon that all samples show no significant conductivity increase at the temperature of the phase
transition (∼ 577 °C) from β to α phase of pure Li2SO4. This transition has important significance for applications. The conductivity of the two-phase film materials has been greatly
enhanced, where the xLi2SO4-(1-x)Al2O3 (x=58) sample shows the highest conductivity, about 1 S/cm at 600 °C; the activation energy decreases with increasing Li2SO4 content. These results agree with the so called composite effect for the conductivity enhancement observed earlier for two-phase
bulk materials.
Based on the four-step proton conducting mechanism in sulphate-based materials, this work may propose a new mechanism. The
protons might jump in a water network associated with the water molecular re-orientation, which is accompanied with the single
proton jump of the four-step transportation among SO
4
2−
groups from one Li2SO4 molecule to another. The former mechanism occur in the interfacial region between the Li2SO4 and the Al2O3 grains, while the latter occur in the bulk of the Li2SO4 grains. These thin film materials are intended for use as proton conducting ceramic membranes in applications such as desulphurisation
and fuel cell co-generation plants.
Paper presented at the 5th Euroconference on Solid State Ionics, Benalmádena, Spain, Sept. 13–20, 1998. 相似文献
7.
A method for the use of natural orbital iterations in limited CI calculations is discussed. This method is then applied to the ground X2II state of the nitric oxide molecule at its experimental equilibrium internuclear separation to yield the total energy, dipole moment, spin densities at each nucleus, and approximate natural spin orbitals for this molecule. 相似文献
8.
The sorption of Pu(VI) onto TiO(2) was studied as a function of pH (2-10) and Pu concentration (10(-8)-10(-4) M) under an N(2) atmosphere, in 0.016 and 0.1 M NaClO(4). A batch-wise method was used, in which pH was measured in separate experimental containers after removal of a sample to determine the amount of Pu that had been sorbed. As Pu is radioactive, it was used as a tracer and measured by liquid scintillation counting. No ionic strength dependence was discerned, which was taken as an indication of inner sphere complex formation. In the interval of pH 2-7 the system could be described by the formation of two positively charged surface complexes using a 1-pK Stern model. Sorption of the plutonyl ion (PuO(2)(2+)) and the first hydrolysis species (PuO(2)(OH)(+)) was estimated using FITEQL to logK(1)=6.9 and logK(2)=1.4, respectively. 相似文献
9.
The electrical properties of Gd0.1Ce0.9O1.95 were investigated in various gas atmospheres using a.c. impedance spectroscopy. In dry oxygen, impedance spectra consisted
of two arcs at low temperatures corresponding to bulk and grain boundary behaviour, respectively, and only one arc at high
temperatures (T>550 °C). The results showed a high oxygen ion conductivity in oxygen atmosphere more than 10−2 S/cm at 600 °C. In water atmospheres, the bulk arc in dry oxygen was reduced by 30 %, and an additional arc corresponding
to the grain boundary effect appeared. It seems that the presence of water may decrease the bulk resistance, but causes an
additional grain boundary resistance and thus increase in the total resistance. In hydrogen atmosphere, a conductivity enhancement
up to one order of magnitude was observed. In hydrogen there is a reduction of Ce4+ to Ce3+ in the sample, which involves defect formation generating e.g. electrons, additional oxygen vacancies and at the same time
protons in the lattice. These new charge carriers are responsible for a significant conductivity enhancement. Therefore, in
a hydrogen atmosphere the material is a mixed (oxygen ion + proton + electron) conductor.
Paper presented at the 6th Euroconference on Solid State Ionics, Cetraro, Calabria, Italy, Sept. 12–19, 1999. 相似文献
10.
Martin Sahlberg Premysl Beran Thomas Kollin Nielsen Yngve Cerenius Krisztina Kads Marko P.J. Punkkinen Levente Vitos Olle Eriksson Torben R. Jensen Yvonne Andersson 《Journal of solid state chemistry》2009,182(11):3113-3117
A novel aluminium rich alloy for hydrogen storage has been discovered, ScAl0.8Mg0.2, which has very promising properties regarding hydrogen storage capacity, kinetics and stability towards air oxidation in comparison to hydrogen absorption in state-of-the-art intermetallic compounds. The absorption of hydrogen was found to be very fast, even without adding any catalyst, and reversible. The discovered alloy crystallizes in a CsCl-type structure, but decomposes to ScH2 and Al(Mg) during hydrogen absorption. Detailed analysis of the hydrogen absorption in ScAl0.8Mg0.2 has been performed using in situ synchrotron radiation powder X-ray diffraction, neutron powder diffraction and quantum mechanical calculations. The results from theory and experiments are in good agreement with each other. 相似文献