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131.
Alexander A. Kodentsov Jorma K. Kivilahti Frans J. J. van Loo 《Monatshefte für Chemie / Chemical Monthly》2005,36(1):1861-1869
The use of equilibrium thermodynamics in describing interfacial reactions between non-ionic inorganic solids is demonstrated
using examples of high-temperature interactions in the Ti–Si–N and Mo–Si–N systems. In the case of a diffusion-controlled
process, solid-state reactions can be interpreted with chemical potential (activity) diagrams. The role of volatile reaction
products formed during interaction in developing the diffusion zone morphology is analysed. The interfacial phenomena in systems
based on dense Si3N4 and non-nitride forming metals can be explained by assuming a nitrogen pressure build-up at the contact surface. This pressure
determines the chemical potential of Si at the interface and, hence, the reaction products in the diffusion zone. 相似文献
132.
Alexander A.?KodentsovEmail author Jorma K.?Kivilahti Frans J. J.?van Loo 《Monatshefte für Chemie / Chemical Monthly》2005,136(11):1861-1869
Summary. The use of equilibrium thermodynamics in describing interfacial reactions between non-ionic inorganic solids is demonstrated
using examples of high-temperature interactions in the Ti–Si–N and Mo–Si–N systems. In the case of a diffusion-controlled
process, solid-state reactions can be interpreted with chemical potential (activity) diagrams. The role of volatile reaction
products formed during interaction in developing the diffusion zone morphology is analysed. The interfacial phenomena in systems
based on dense Si3N4 and non-nitride forming metals can be explained by assuming a nitrogen pressure build-up at the contact surface. This pressure
determines the chemical potential of Si at the interface and, hence, the reaction products in the diffusion zone. 相似文献
133.
Vähäoja P Närhi J Kuokkanen T Naatus O Jalonen J Lahdelma S 《Analytical and bioanalytical chemistry》2005,383(2):305-311
A new infrared spectroscopic method suitable for determining total fatty alcohol and fatty acid ester concentrations in industrial
oils has been developed. Oil samples were diluted with toluene (1:3 w/w), the toxicity and volatility of which are relatively
low compared with more commonly used IR solvents, like carbon tetrachloride or carbon disulfide. Mixture standards were prepared
from dodecanol, tetradecanol, octadecanol, methyl stearate and methyl palmitate. Some analytical and statistical tests were
performed on the developed method. The recoveries and the repeatability of the method proved to be sufficient for the quantitative
determination of fatty alcohol and fatty acid ester additives in industrial oils. Reproducibility testing in another laboratory
also produced satisfactory results. The developed method also proved to be relatively quick and simple. This method was developed
to satisfy industry’s need to determine the concentrations of these oil additives, and it has already been applied successfully
in machinery oil analysis. 相似文献
134.
Luminescence emission and uv-excitation properties of LaOBr: Tb3+, LaOBr: Ce3+, and LaOBr: Tb3+, Ce3+ phosphors were studied. The visible emission spectra of La0.995Tb0.005OBr consists of5D3,4 →7F3–6 transitions in the wavelength range of 410–630 nm. The excitation of the Tb3+ ion gives a broad 4f → 5d transition band at 254 nm and weaker4f → 4f transition lines above 300 nm. The uv-excitation and emission of La0.995Ce0.005OBr at 290, 315, 355 (excitation), and 440 nm (emission) originate from transitions between the 4f-ground state and the four crystal field components of the5d2D excited state. The sensitization of Tb3+ luminescence in LaOBr with Ce3+ at varying concentrations is described and discussed. With increasing Ce3+ concentration the 5D3 →7F transitions of Tb3+ quench totally and the5D4 →7F transitions begin to quench gradually. The excitation spectrum of the5D4 →7F5 transition of Tb3+ consists of four bands due to Tb3+ and Ce3+, of which the three Ce3+ bands increase in intensity and the Tb3+ band decreases as the Ce3+ concentration is increased. 相似文献
135.
Jorma Kaarlo Merikoski 《BIT Numerical Mathematics》1979,19(1):39-42
A lower boundn
–1
i,k
aik for the Perron eigenvalue of a symmetric non-negative irreducible matrixA=(a
ik) is studied and compared with certain other lower bounds. 相似文献
136.
Using chromatographic, infrared and mass spectrometric methods. 44 different organic compounds, besides water and ammonia have been separated and identified from the pyrolysis products of nickel(II) aniline nitrate hydrate. The nickel(II) aniline chloride, bromide, iodide and sulphate complexes, however, showed only aniline, formed by dissociation as an organic pyrolysis product; this is in accordance with previous conclusions drawn from thermogravimetric (TG) curves.On the basis of these results it is advisable to proceed with a certain caution when drawing conclusions from TG curves on pyrolysis processes without specification analyses of the process products. This should be specially noted when the reaction is abrupt and not calculable from the corresponding part of the TG curve, that is not smooth, preferably of S-shape.The formation of the main pyrolysis products through radical reactions is duscussed. 相似文献
137.
138.
Sarpola AT Saukkoriipi JJ Hietapelto VK Jalonen JE Jokela JT Joensuu PH Laasonen KE Rämö JH 《Physical chemistry chemical physics : PCCP》2007,9(3):377-388
ElectroSpray Ionization-Mass Spectrometry (ESI-MS) and computational methods (DFT, MP2, and COSMO) were used to investigate the hydrolysis products of aluminium chloride as a function of sulfate concentration at pH 3.7. With the aid of computational chemistry, structural information was deduced from the chemical compositions observed with ESI-MS. Many novel types of hydrolysis products were noted, revealing that our present understanding of aluminium speciation is too simple. The role of counterions was found to be critical: the speciation of aluminium changed markedly as a function of sulfate concentration. Ab initio calculations were used to reveal the energetically most favoured structures of aluminium sulfate anions and cations selected from the ESI-MS results. Several interesting observations were made. Most importantly, the bonding behaviour of the sulfate group changed as the number of aqua ligands increased. The accompanying structural rearrangement of the clusters revealed the highly active role of sulfate as a ligand. The gas phase calculations were expanded to the aquatic environment using a conductor-like screening model. As expected, the bonding behaviour of the sulfate group in the minimum energy structures was distinctly different in the aquatic environment compared to the gas phase. Together, these methods open a new window for research in the solution chemistry of aluminium species. 相似文献
139.
140.