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81.
A. V. Varlamov A. I. Komarova A. N. Levov E. V. Savitkina A. P. Krapivko V. N. Khrustalev E. A. Sorokina L. N. Kulikova E. V. Nikitina V. P. Zaytsev F. I. Zubkova 《Russian Chemical Bulletin》2010,59(5):1014-1022
7-Nitropyridobenzimidazolium salts are cleaved with secondary amines to form 2-[(E,E)-4-aminobuta-1,3-dienyl]-1H-benzimidazoles. The latter react with dimethyl acetylene-dicarboxylate to yield 4a-[(E,Z,E)-6-amino-4,5-dimethoxycarbonylhexa-1,3,5-trien-1-yl]-1,2,3,4-tetra(methoxycarbonyl)-4a,5-dihydropyrido[1,2-a]benzimidazoles. 相似文献
82.
F.?I.?ZubkovEmail author E.?V.?Nikitina V.?P.?Zaytsev V.?N.?Khrustalev R.?A.?Novikov R.?S.?Borisov A.?V.?Varlamov 《Chemistry of Heterocyclic Compounds》2012,48(5):785-794
On the basis of a transition state conformation analysis, an attempt was made to explain the high chemoselectivity of intramolecular [4 + 2] cycloaddition in 3-alkyl-2,6-difuryl-N-maleylpiperidin-4-ones. It was shown that the thermal Diels–Alder reaction in these piperidine derivatives takes place through the “boat” conformation and leads to the formation of hydrogenated 1-alkyl-4-(2-furyl)-2H-8,10a-epoxy-pyrido[2,1-a]isoindol-2-ones. The alternative regioisomers, 3-alkyl-4-(2-furyl)-2H-8,10a-epoxy-pyrido[2,1-a]isoindol-2-ones, are hardly formed at all. At the same time, the intramolecular Diels–Alder reaction in the isostructural 3-alkyl-N-allyl-2,6-difurylpiperidin-4-ones, takes place non-regioselectively from the “chair” conformation. 相似文献
83.
84.
A.E. Asratyan V.Sh. Epstein E.A. Grigoriev N.V. Kalganov V.S. Kaftanov V.D. Khovansky Yu.G. Kornelyuk M.A. Kubantsev I.P. Maksimov A.N. Rozanov M.S. Ryabinin V.M. Serezhin V.V. Shamanov V.G. Shevchenko V.A. Smotryaev I.S. Trostin A.A. Zaytsev S.A. Zeldovich Ya.A. Zudin 《Physics letters. [Part B]》1977,71(2):439-442
A search for dimuons produced in a spark chamber experiment in neutrino and antineutrino beams of the Serpukhov accelerator is reported. The clear dimuon signal has been observed in vN interactions. Rv = N(2ω)/N(1ω)? (6.2 ± 1.7) × 10?3 in the energy interval 7.5 ÷ 30 GeV. From antineutrino data we conclude that in the same energy range . 相似文献
85.
Andrey V. Zaytsev 《Tetrahedron》2005,61(24):5831-5836
The polyfunctionalised pyrrole, 3,5-dichloro-1H-pyrrole-2,4-dicarbaldehyde reacts with secondary amines by condensation with the 2-carbaldehyde to give methylene-substituted pyrroles, while its N-alkyl derivatives undergo substitution of the 5-chloro group to give 5-substituted pyrroles. 相似文献
86.
Piotr Pander Ruth Daniels Andrey V. Zaytsev Ashleigh Horn Amit Sil Thomas J. Penfold J. A. Gareth Williams Valery N. Kozhevnikov Fernando B. Dias 《Chemical science》2021,12(17):6172
A novel dinuclear platinum(ii) complex featuring a ditopic, bis-tetradentate ligand has been prepared. The ligand offers each metal ion a planar O^N^C^N coordination environment, with the two metal ions bound to the nitrogen atoms of a bridging pyrimidine unit. The complex is brightly luminescent in the red region of the spectrum with a photoluminescence quantum yield of 83% in deoxygenated methylcyclohexane solution at ambient temperature, and shows a remarkably short excited state lifetime of 2.1 μs. These properties are the result of an unusually high radiative rate constant of around 4 × 105 s−1, a value which is comparable to that of the very best performing Ir(iii) complexes. This unusual behaviour is the result of efficient thermally activated reverse intersystem crossing, promoted by a small singlet–triplet energy difference of only 69 ± 3 meV. The complex was incorporated into solution-processed OLEDs achieving EQEmax = 7.4%. We believe this to be the first fully evidenced report of a Pt(ii) complex showing thermally activated delayed fluorescence (TADF) at room temperature, and indeed of a Pt(ii)-based delayed fluorescence emitter to be incorporated into an OLED.Efficient thermally activated delayed fluorescence (TADF) in a brightly luminescent diplatinum(ii) complex results in significant enhancement of the radiative decay rate. 相似文献
87.
88.
The examples of phase transitions in Langmuir-Blodgett films of polyvinylidene fluoride (PVDF) and in the surface layer of polystyrene were chosen to demonstrate the great potential of using luminescent molecular probes for studying the heterogeneity of the surfaces of solids and thin films, as well as structural transformations and phase transitions in systems of different natures. The method provides unique information on the local properties of surfaces and thin films when used in combination with other techniques. 相似文献
89.
Dr. Andrey V. Zaytsev Dr. Rachel Bulmer Prof. Valery N. Kozhevnikov Dr. Mark Sims Dr. Giuseppe Modolo Dr. Andreas Wilden Dr. Paul G. Waddell Dr. Andreas Geist Prof. Petra J. Panak Patrik Wessling Dr. Frank W. Lewis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(2):428-437
The synthesis and evaluation of three novel bis-1,2,4-triazine ligands containing five-membered aliphatic rings are reported. Compared to the more hydrophobic ligands 1 – 3 containing six-membered aliphatic rings, the distribution ratios for relevant f-block metal ions were approximately one order of magnitude lower in each case. Ligand 10 showed an efficient, selective and rapid separation of AmIII and CmIII from nitric acid. The speciation of the ligands with trivalent f-block metal ions was probed using NMR titrations and competition experiments, time-resolved laser fluorescence spectroscopy and X-ray crystallography. While the tetradentate ligands 8 and 10 formed LnIII complexes of the same stoichiometry as their more hydrophobic analogues 2 and 3 , significant differences in speciation were observed between the two classes of ligand, with a lower percentage of the extracted 1:2 complexes being formed for ligands 8 and 10 . The structures of the solid state 1:1 and 1:2 complexes formed by 8 and 10 with YIII, LuIII and PrIII are very similar to those formed by 2 and 3 with LnIII. Ligand 10 forms CmIII and EuIII 1:2 complexes that are thermodynamically less stable than those formed by ligand 3 , suggesting that less hydrophobic ligands form less stable AnIII complexes. Thus, it has been shown for the first time how tuning the cyclic aliphatic part of these ligands leads to subtle changes in their metal ion speciation, complex stability and metal extraction affinity. 相似文献