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71.
72.
The method for the synthesis of indoles from nitropyridinium salts has been improved. A method for synthesizing novel derivatives of indoleninium quaternary salts has been developed. The condensation of indoleninium salts with formyl derivatives of crown ethers leading to styryl dyes is described. Photoisomerization and complexing of crown-ether dyes with ions of alkaline and alkaline-earth metals have been studied. The shift of the long-wave absorption maximum has been observed to depend on the size and charge density of the metal cation.For communication 8, see ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1625–1632, September, 1993. 相似文献
73.
V. B. Nazarov V. G. Avakyan S. P. Gromov M. V. Fomina T. G. Vershinnikova V. Yu. Rudyak M. V. Alfimov 《Russian Chemical Bulletin》2007,56(2):281-289
The electronic absorption spectra and fluorescence spectra of 4-(2-naphthyl)pyridine (1), 2-(4-methyl-2-pyridyl)-4-(2-naphthyl)pyridine (2), and 4-(2-naphthyl)-2-phenylpyridine (3) in solutions and in complexes with β-cyclodextrin (β-CD) and well water-soluble hydroxy-propyl-β-cyclodextrin (HP-β-CD)
were studied. Fluorescence near 475 nm observed in aqueous solutions of compounds 1–3 arises from protonated forms of these compounds produced in the excited state. Results of DFT quantum chemical calculations
show an increase in proton affinity energies of excited-state naphthylpyridines 2 and 3. The formation of inclusion complexes with cyclodextrins makes protonation of compounds 2 and 3 more difficult, which manifests in large hypsochromic shifts of fluorescence band maxima. The stability constants of the
complexes 1·HP-β-CD and 2·HP-β-CD determined from their fluorescence spectra are 3425 and 3760 L mol−1, respectively. The stability constant of the complex 3·HP-β-CD (5500±600 L mol−1) was found from the changes in the solubility of naphthylpyridine 3 in water upon complexation. Semiempirical quantum chemical calculations of the molecular structures and thermodynamic characteristics
of pseudorotaxane inclusion complexes of trans-2, cis-2, and trans-2·H2O with HP-β-CD were carried out.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 272–280, February, 2007. 相似文献
74.
Fomina I. G. Sidorov A. A. Aleksandrov G. G. Zhilov V. I. Ikorskii V. N. Novotortsev V. M. Eremenko I. L. Moiseev I. I. 《Russian Chemical Bulletin》2004,53(1):118-126
The reaction of the dinuclear complex Co2(-OOCCMe3)2(2-OOCCMe3)2bpy2 (1) with the polymer [Co(OH)
n
(OOCCMe3)2–n
]
x
afforded the unsymmetrical dinuclear complex bpyCo2(2-O,2-OOCCMe3)(2-O,O"-OOCCMe3)2(2-OOCCMe3) (2). The reaction of 2,2"-dipyridylamine with [Co(OH)
n
(OOCCMe3)2–n
]
x
gave rise to the analogous complex [(C5H4N)2NH]Co2(2-O,2-OOCCMe3)(-OOCCMe3)2(2-OOCCMe3) (3). The reaction of complex 1 with Ni4(3-OH)2(-OOCCMe3)4(OOCCMe3)2(MeCN)2[2-o-C6H4(NH2)(NHPh)]2 (4) produced an isostructural heterometallic analog of complex 2 with composition bpyM2(2-O,2-OOCCMe3)(2-O,O"-OOCCMe3)2(2-OOCCMe3) (5) (M = Co, Ni; Co : Ni = 1 : 1) and the dinuclear heterometallic complex bpy(HOOCCMe3)M(-OH2)(-OOCCMe3)2M(OOCCMe3)2[o-C6H4(NH2)(NHPh)] (6) (M = Co, Ni; Co : Ni = 0.15 : 1.85). Compounds 2 and 5 exhibit ferromagnetic spin-spin exchange interactions. 相似文献
75.
Microstructure and Chemical Bonding in Silicon Carbonitride Films Synthesized by Plasma Enhanced Chemical Vapor Deposition 总被引:1,自引:0,他引:1
T. P. Smirnova A. M. Badalyan V. O. Borisov L. V. Yakovkina V. V. Kaichev A. N. Shmakov A. V. Nartova V.I. Rakhlin A. N. Fomina 《Journal of Structural Chemistry》2003,44(1):169-173
Silicon carbonitride films were synthesized by plasma enhanced chemical vapor deposition using silyl derivatives of asymmetric dimethylhydrazine, (CH3)2HSiNHN(CH3)2 and (CH3)2Si[NHN(CH3)2]2, as molecular precursors. The film material consists of an amorphous matrix with nanocrystalline inclusions. Indexing of synchrotron radiation Xray diffraction patterns suggests that the structure of the nanocrystals is tetragonal with lattice parameters a = 9.6 and c = 6.4. Xray photoelectron spectra indicate that Si—N and C—N sp
3 hybrid bonds are predominant. The absence of G or Dmodes in Raman spectra, which are otherwise typical of structures possessing sp
2 bonding, provides further support for the tetragonal structure of the nanocrystals. 相似文献
76.
Ling J Fomina N Rasul G Hogen-Esch TE 《The journal of physical chemistry. B》2008,112(33):10116-10122
The dilute solution properties of poly(9,9-dihexylfluorene-2,7-diyl) (PDHF) were studied by coupled SEC/light scattering and MALDI-TOF over a large molecular weight (MW) span ranging from PDHF oligomers (1-8-mer) to high MW polymer. The results were compared with Monte Carlo simulations based on realistic PDHF models obtained from X-ray data and density functional theory (DFT) calculations and with a DFT based Kratky-Porod-Benoit-Doty (KPBD) worm-like chain. The simulations called "selective random walk" (SRW) and the corresponding "selective self-avoiding random walk" (SSAW) explicitly take into account the rotationally labile bonds between the fluorene units in that four distinct torsion angles (+/-37.5 and +/-143 degrees) between the units are chosen randomly. The simulations better account than the KPBD model for the experimental data obtained by us and others for various poly(9,9-dialkylfluorene-2,7-diyl) polymers but still give somewhat larger values for the radii of gyration and hydrodynamic volumes. The torsion angle selectivity of the SRW and SSAW simulations predict long chain sections punctuated by sudden sharp loops. 相似文献
77.
V. B. Nazarov V. G. Avakyan S. P. Gromov M. V. Fomina T. G. Vershinnikova M. V. Alfimov 《Russian Chemical Bulletin》2004,53(11):2525-2531
The electronic absorption and fluorescence spectra of 4-(2-naphthyl)pyridine (1) and N-methyl-4-(2-naphthyl)pyridinium perchlorate (2
+·ClO4
–) were studied in aqueous solutions in the absence and presence of -cyclodextrin (-CD). In aqueous solutions and organic solvents in the presence of water or H+ ions, compound 1 exhibits intense fluorescence with a maximum at 21 270 cm–1, and its quantum yield in an aqueous solution is 0.9±0.09. The same fluorescence spectrum was detected for an aqueous solution of 2
+·ClO4
–. In an aqueous solution, compound 1 and -CD form stable fluorescing supramolecular 2:2 complexes, whose structure was calculated by the quantum-chemical MNDO/PM3 method. The formation of these complexes induces a hypsochromic shift of the fluorescence maximum of 1 by 5000 cm–1. The stability constant of the complex is 2·103 L mol–1. A decrease in the pH results in the formation of a protonated form of 1(1·H+) and destruction of the complex, thus favoring the escape of the substrate from the -CD cavity. The quantum-chemical calculations showed that the insertion of 1 into the -CD cavity is thermodynamically more favorable than hydration; on the contrary, the formation of 1·H+ increases dramatically the hydration energy, which promotes the escape of 1·H+ from the -CD cavity; cation 2
+ does not form a complex with -CD; in the thermodynamically most favorable 2:2 complex, the naphthalene fragments of two molecules 1 are parallel to each other in a broad section of the -CD dimer constructed according to the head-to-head type.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2420–2425, November, 2004. 相似文献
78.
Shipovskaya A. B. Malinkina O. N. Fomina V. I. Rudenko D. A. Shchegolev S. Yu. 《Russian Chemical Bulletin》2015,64(5):1172-1177
Russian Chemical Bulletin - The optical activity of solutions, oligomers, and films of chitosan acetate in a molecular weight (М) range of 660—640 000 g mol–1 was studied by the... 相似文献
79.
Resin ED-20 hardening by an oligoaminoamide hardener is analyzed by the differential scanning calorimetry (DSC) method. The optimal resin-to-hardener proportion is determined. Physical, mechanical, and thermal characteristics of the hardened polymers are determined. The high adhesive ability of the oligoaminoamide mixture towards steel is analyzed. 相似文献
80.
A. L. Emelina Zh. V. Dobrokhotova A. A. Sinelshchikova Yu. A. Velikodnyi I. G. Fomina P. S. Koroteev V. M. Novotortsev I. L. Eremenko 《Russian Journal of Inorganic Chemistry》2010,55(11):1754-1761
Kinetic analysis of the thermolysis of samarium pivalate [Sm2(μ2-OOCCMe3)4(OOCCMe3)2(HOOCCMe3)6] · HOOCCMe3 (1) was carried out (the input data were differential scanning calorimetry (DSC) and thermogravimetry data), and a mathematic
model of the process was developed that allowed us to optimize (by calculation) the conditions for formation of {Sm(OOCCMe3)3}
n
(2) samarium tris-pivalate via thermal decomposition of complex 1. The results of the thermal study of samarium and gadolinium tris-pivalates in the temperature range of −50…+50°C are reported.
Specific anomalies were found in the DSC curves and heat capacity versus temperature curves in the temperature range of 0–50°C. 相似文献