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21.
Mit"kina T. V. Gerasko O. A. Sokolov M. N. Naumov D. Yu. Fedin V. P. 《Russian Chemical Bulletin》2004,53(1):80-85
Slow evaporation of hydrochloric acid solutions of zirconium(iv) or hafnium(iv) oxochlorides and cucurbituril in air afforded compounds with composition [M4(OH)8(H2O)16]Cl8·(C36H36N24O12)·16H2O, where M = Zr (1) or Hf (2). According to the X-ray diffraction data, complexes 1 and 2 are isostructural. Their crystal structures can be described as packings of polymer chains consisting of alternating cucurbituril molecules and tetranuclear cations [M4(OH)8(H2O)16]8+ linked to each other via an extensive network of hydrogen bonds. Compound 2 is the first structurally characterized tetranuclear hafnium aqua complex. 相似文献
22.
V. A. Mamedov I. A. Litvinov F. G. Sibgatullina O. N. Kataeva I. A. Nuretdinov V. A. Naumov 《Chemistry of Heterocyclic Compounds》1994,30(2):169-172
Condensation of benzalaniline with N,N-dimethylamide of dichloroacetic acid under Darzens reaction conditions was used to obtain r-1, t-3-diphenyl-c-2-chloro-2-(NN-dimethylcarbamoyl)aziridine. The structure was established by x-ray diffraction analysis. Stabilization of the position of the substituents at the atoms of the aziridine ring by the hyperconjugation interaction of the unshared electron pair of the nitrogen atom with the antibonding orbital of the C-CI bond is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 189–192, February, 1994. Original article submitted November 30, 1993. 相似文献
23.
Internal rotation about the P?C bonds in the Cl2PCH=CH2 and Cl2PCH=CMe2 molecules is diseussed. It is shown that the cis (with eclipsed C=C bonds and lone electron pair of the phosphorus atom) and eclipsed conformers of the Cl2PCH=CH2 molecule are in equilibrium. The geometrical parameters and conformation compositions are refined. The content of the cis conformer is 40%. The Cl?P?C=C torsion angles are ±128.5° for the cis conformer and ?29.6 and ?132.6° for the eclipsed conformer. The Cl2PCH=CMe2 molecule occurs only in the cis form. For Cl2PCH=CMe2, the geometrical parameters are as follows: bond lengths C?H=1.124(11), C=C=1.322(8), P?C=1.789(3), and P?Cl=2.042(2) Å; bong angles (deg) C?P?Cl=99.1(4), Cl?P?Cl=99.6(6), C=C?CH3=120.1 and 125.7, and P?C=C=122.3(9); torsion angles Cl?P?C=C=±129.3(3). 相似文献
24.
N. G. Naumov K. A. Brylev S. Cordier O. Hernandez C. Perrin V. E. Fedorov 《Journal of Structural Chemistry》2003,44(4):698-703
Two new compounds containing molybdenum thiocyanide cluster anions, K6[Mo4S4(CN)12]·10H2O (1) and (18-crown-6K)8[Mo6S6(CN)16]·17.5H2O (2), were synthesized and investigated by X-ray structure analysis. Crystal data: a=11.8430(17), b=11.8430(17), c=35.170(7) , V=4932.8(14) 3, space group I41/a, Z=4, dcalc=1.563 g/cm3 for 1; a=28.7513(5), b=18.4190(3), c=20.7586(4) , =118.5982(7)°, V=9651.9(3) 3, space group C2/m, Z=4, dcalc =1.563 g/cm3 for 2. The [Mo4S4(CN)12]6- cluster anion in 1 has an ordinary structure typical of cubane transition metal complexes. In the structure of the [Mo6S6(CN)16]8- anion of 2, two crystallographically independent molybdenum atoms form a Mo6 metallocluster, represented as two edge-sharing tetrahedra. 相似文献
25.
V. A. Naumov G. V. Girichev M. A. Tafipol'skii 《Russian Journal of General Chemistry》2005,75(12):1949-1955
Gas-phase electron diffraction and HF/6-31G*, HF/6-31G**, and B3LYP/6-31G* ab initio calculations were used to find that in the gas phase at 242°C the calix[4]arene [-(C6H3OH)-CH2-]4 molecule possesses a C4 conformation. Geometric parameters of the molecule were determined, and the energies of C-H?O hydrogen bonds (7.3 kcal mol?1) were estimated by the AM1 method. 相似文献
26.
O. G. Shakirova D. Yu. Naumov Yu. G. Shvedenkov N. I. Alferova G. V. Dolgushin L. G. Lavrenova 《Journal of Structural Chemistry》2003,44(4):642-649
A new trinuclear nickel(II) complex with 4-(pyridyl-2)-1,2,4-triazole (pytrz), [Ni3(pytrz)6(H2O)6](NO3)6, has been synthesized, and its crystal structure has been determined. The compound was studied by X-ray phase analysis (XRPA), magnetochemical measurements, and electronic and IR spectroscopy. 相似文献
27.
V. A. Naumov H. Oberhammer M. A. Tafipol’skii 《Russian Journal of General Chemistry》2005,75(6):845-850
Geometric parameters and conformation of the bis(trimethylsilyl)hypophosphite molecule were determined by gas-phase electron diffraction and quantum-chemical calculations. The molecule has an asymmetric structure, including an asymmetric P(OSiMe3)2 group. The principal geometric parameters are as follows: (r
a; in parentheses are standard deviations): bond lengths: P-O 1.616 and 1.633(1), Si-O 1.670(1), Si-C 1.892(1), C-H 1.097(3) Å; bond angles: OPO 100.8(8), POSi 133.3, and 138.4(3)°; torsion angles about P-O bonds 120(2) and 41.(3)°; and torsion angles about Si-O bonds are 145 and −178(4)°.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 897–902.Original Russian Text Copyright © 2005 by Naumov, Oberhammer, Tafipol’skii. 相似文献
28.
Using some special experimental techniques for anisotropic refinement of the crystal structure of [Co(NH3)5NO2]Cl2 at high pressures gave results with an accuracy comparable to that obtained in normal conditions. The anisotropy of lattice
compression under pressure is determined by specific interactions in crystals, in particular, by NH-Cl and NH-O hydrogen bonds.
The anisotropy of compression at increased pressure is qualitatively distinct from that caused by lowered temperature for
the same structure. This difference is also due to specific interactions (hydrogen bonds) in the structure.
Institute of Solid State Chemistry, Siberian Branch, Russian Academy of Sciences (Novosibirsk). Novosibirsk State University.
Marburg University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 3, pp. 433–447, May–June, 1998.
This work was supported by A. Humboldt Foundation. 相似文献
29.
Spectra of single tetra-tert-butylterrylene chromophore molecules embedded in an amorphous polyisobutylene matrix as microprobes were recorded. The individual temperature dependences of the spectral linewidths for the same single molecules (SMs) in a broad temperature interval (1.6 < T < 40 K) have been measured. This enabled us to separate the contributions of tunneling two-level systems and quasilocalized low-frequency vibrational modes (LFMs) to the observed linewidths. The analysis of the T dependences yields the values of LFM frequencies and SM-LFM coupling constants for the LFMs in the local environment of a given chromophore. Pronounced distributions of the observed parameters of LFMs were found. This result can be regarded as the first direct experimental proof of the localized nature of LFMs in glasses. 相似文献
30.
Naumov N. G. Artemkina S. B. Virovets A. V. Fedorov V. E. 《Russian Journal of Coordination Chemistry》2004,30(11):792-799
The [{Mn(H2O)3}2{Re6Se8(CN)6}] · 3.3H2O complex was produced on slow evaporation of an aqueous solution containing the salt of a cluster complex K4Re6Se8(CN)6 · 3.5H2O and a 23-fold excess of Mn2+. The cluster complexes [Re6Se8(CN)6]4– are linked in a crystal into the charged coordination layers [{Mn(H2O)3}4{Re6Se8(CN)6}3]4–
2 through the Mn2+ cations. The Mn2+ cations are coordinated in a layer by three cyano nitrogen atoms of the cluster complexes; the Mn–N bond lengths are 2.13(4) and 2.21(2) Å. Each [Re6Se8(CN)6]4– anion is bonded to three manganese cations Mn(1). The anions are bonded additionally to the Mn(2) cations disordered over two close positions. 相似文献