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51.
Very simple formulas have been derived, which make possible the calculation with a high accuracy of the Madelung and dispersion contributions to the binding energy of an ion on the unrelaxed surface of a NaCl-type crystal. The formulas can be applied to practically all possible positions of a surface ion. 相似文献
52.
Anna Wrona-Piotrowicz Lucjan Jerzykiewicz 《Journal of organometallic chemistry》2011,696(23):3826-3830
The title compound has been synthesized in the reaction of ferrocene with ethoxycarbonyl isocyanate in methanesulfonic acid. It has been found that it undergoes N-alkylation with benzyl alcohols under classical Mitsunobu conditions (PPh3/DEAD). However, in the reaction with cholesterol and stigmasterol O-alkylation with inversion of configuration occurred (confirmed by hydrolysis of the product obtained from cholesterol to epicholesterol). The structure of the product obtained from p-nitrobenzyl alcohol was determined by X-ray diffraction. 相似文献
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54.
Marek T. Cegla Marzena Baran Agnieszka Czarny Marek Zylewski Joanna Potaczek Jeff Klenc Lucjan Strekowski 《Journal of heterocyclic chemistry》2011,48(3):720-723
Fused dihydrooxazoles are produced by the reaction of 8‐bromoteophylline (1), 6‐bromo‐2‐pyridone (7), or 2‐bromobenzimidazole (11) with an N‐substituted N‐(2,3‐epoxypropyl)amine. The product derived from 1 undergoes rearrangement to a fused dihydrooxazine while the fused dihydrooxazoles derived from 7 and 11 are stable. J. Heterocyclic Chem., (2011). 相似文献
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56.
Lucjan Strekowski Hyeran Lee J. Christian Mason Martial Say Gabor Patonay 《Journal of heterocyclic chemistry》2007,44(2):475-477
Relative stabilities of methanolic solutions of dyes that are potentially important for labeling of biological macromolecules with a visible‐red or near‐infrared fluorophore were evaluated in the presence of molecular oxygen under dark and light conditions. 相似文献
57.
Pozharskii AF Degtyarev AV Ryabtsova OV Ozeryanskii VA Kletskii ME Starikova ZA Sobczyk L Filarowski A 《The Journal of organic chemistry》2007,72(8):3006-3019
A regular set of 2-(alpha-hydroxymethyl)- and 2,7-di(alpha-hydroxymethyl)-1,8-bis(dimethylamino)naphthalenes has been prepared. Their X-ray, NMR, and IR studies have demonstrated that in tertiary mono-alcohols the orientation of free nitrogen electron pairs in crystals and solution corresponds to nonconventional in/out conformers stabilized by O-H...N intramolecular hydrogen bonding. For tertiary 2,7-dialcohols, the superimposed equilibrating in/out-out/in nitrogen invertomers are observed in solution. Unlike this, primary and secondary mono- and dialcohols commonly exist in the in/in form, which is typical for the parent proton sponge and the majority of its derivatives. 相似文献
58.
Janusz Jacak Patrycja Łydżba Lucjan Jacak 《The European Physical Journal B - Condensed Matter and Complex Systems》2017,90(5):90
In this paper the topological approach to quantum Hall effects is carefully described. Commensurability conditions together with proposed generators of a system braid group are employed to establish the fractional quantum Hall effect hierarchies of conventional semiconductors, monolayer and bilayer graphene structures. Obtained filling factors are compared with experimental data and a very good agreement is achieved. Preliminary constructions of ground-state wave functions in the lowest Landau level are put forward. Furthermore, this work explains why pyramids of fillings from higher bands are not counterparts of the well-known composite-fermion hierarchy – it provides with the cause for an intriguing robustness of ν = 7/3 , 8/3 and 5/2 states (also in graphene). The argumentation why paired states can be developed in two-subband systems (wide quantum wells) only when the Fermi energy lies in the first Landau level is specified. Finally, the paper also clarifies how an additional surface in bilayer systems contributes to an observation of the fractional quantum Hall effect near half-filling, ν = 1/2 . 相似文献
59.
Hyeran Lee Mikhail Y. Berezin Maged Henary Lucjan Strekowski Samuel Achilefu 《Journal of photochemistry and photobiology. A, Chemistry》2008,200(2-3):438-444
Structurally diverse near-infrared (NIR) absorbing polymethine dyes were prepared and their fluorescence lifetimes (FLT) were evaluated in relation to their structural features. Comparative FLT analysis based on the modification of methine chain length and heterocyclic system showed that indolium or benzo[e]indolium heptamethine dyes exhibited longer FLT than the benzo[c,d]indolium trimethine dye. Modification of heterocyclic system alone with an intact chain length showed that indolium-based heptamethine dyes showed approximately 30% longer FLT than the benzo[e]indolium-based dyes. In general, the FLT of polymethine dyes increased from polar to non-polar solvents. In addition, correlation study between the theoretical and the experimental FLT for indocyanine green (ICG) suggests that the lack of structural rigidity for these cyanine dyes is primarily responsible for the loss of the excited state energy via non-radiative pathway. 相似文献
60.
The cocrystals of adenine and metal (II) quinoline-2-carboxylates (M = Mn2+, Fe2+, Co2+) have been obtained by self-assembly. The complexes are composed of adenine ribbons with the AA22 pairing pattern involving both Watson-Crick and Hoogsteen faces in hydrogen bonding and the neutral molecules of carboxylate positioned in inorganic layers. The very compact supramolecular structure is made by the extensive system of hydrogen bonds and face-to-face pi-pi interactions. 相似文献