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31.
M. B. Shundalau G. A. Pitsevich M. A. Ksenofontov D. S. Umreiko 《Journal of Applied Spectroscopy》2010,77(3):309-314
We present results of ab initio calculations of the structure and vibrational IR spectrum for 4,4′-diphenylmethane-bis(methyl)carbamate
(DPMC). Calculations were carried out in the HF/6-311G approximation with subsequent force-field scaling. The calculated characteristics
of the vibrational spectrum of DPMC show satisfactory agreement with experimental values, which permits them to be used in
spectral and structural analysis 相似文献
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34.
Ulrike Riese Naim Faza Werner Massa Klaus Harms Thees Breyhan Paul Knochel Jürgen Ensling Vadim Ksenofontov Philipp Gütlich Kurt Dehnicke 《无机化学与普通化学杂志》1999,625(9):1494-1499
The phosphoraneiminato complexes [MnBr(NPEt3)]4 ( 1 ) and [M4Br5{NP(NMe2)3}3] with M = Mn ( 2 ) and M = Co ( 3 ) are prepared by melting reactions from the anhydrous metal dibromides with the silylated phosphaneimines Me3SiNPR3 (R = Et, NMe2) in the presence of potassium fluoride. All complexes are characterized by crystal structure analyses. 1 forms an only slightly distorted Mn4N4 heterocubane skeleton with an approximate Td symmetry and short Mn…Mn distances of average 295.7 pm. In the structures of 2 and 3 one μ3-NPEt3 ligand of 1 is replaced by one bromine atom with μ3-function. This leads to the novel heterocubane type M4N3Br with approximate C3 symmetry. The deformation of the cubic skeleton leads to metal-metal distances of different lengths, i. e. 292.7 and 323.6 pm in 2 and 274.4 and 306.2 pm in 3 . Temperature dependent magnetic susceptibility measurements between 300 and 5 K on 1 have shown that strong antiferromagnetic coupling exists between the Mn(II) ions with S = 5/2, with a large negative Weiss constant of Θ = –694 K. 相似文献
35.
Komornikov V. A. Timakov I. S. Zajnullin O. B. Grebenev V. V. Makarova I. P. Selezneva E. V. Ksenofontov D. A. 《Crystallography Reports》2019,64(6):984-990
Crystallography Reports - The phase equilibria in the CsHSO4–CsH2PO4–NH4H2PO4–H2O four-component aqueous salt system have been studied. The crystallization ranges and solubilities... 相似文献
36.
M. B. Shundalov G. A. Pitsevich M. A. Ksenofontov D. S. Umreiko 《Journal of Applied Spectroscopy》2009,76(3):325-333
We present results of ab initio and DFT calculations of the structure, potential functions of the methyl group internal rotation and the amino group inversion,
and vibrational frequencies and intensities in IR and Raman spectra of methylcarbamate. The calculations were carried out
using different basis sets in the HF, MP2, and DFT/B3LYP approximations. The influence of both the basis set size and the
allowance for electronic correlation on peculiarities of the structure of the amino group in methylcarbamate has been analyzed.
It is shown that the B3LYP/6-311++G(2d, p) and B3LYP/cc-pVDZ calculations reproduce highly accurately experimental geometric
parameters of methylcarbamate. Parameters of torsional and inversion potentials and characteristics of vibrational spectra
calculated in different approximations show satisfactory agreement with experimental values.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 3, pp. 349–357, May–June, 2009. 相似文献
37.
M. B. Shundalov G. A. Pitsevich M. A. Ksenofontov D. S. Umreiko 《Journal of Applied Spectroscopy》2007,74(2):199-206
We present theoretical models and results of calculations of the energies of torsional states of dihydroxybenzenes: flexible
molecules with two non-coaxial internal tops of low symmetry.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 178–183, March–April, 2007. 相似文献
38.
Ruben M Ziener U Lehn JM Ksenofontov V Gütlich P Vaughan GB 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,11(1):94-100
Hierarchical self-assembly of complex supramolecular architectures allows for the emergence of novel properties at each level of complexity. The reaction of the ligand components A and B with Fe(II) cations generates the [2x2] grid-type functional building modules 1 and 2, presenting spin-transition properties and preorganizing an array of coordination sites that sets the stage for a second assembly step. Indeed, binding of La(III) ions to 1 and of Ag(I) ions to 2 leads to a 1D columnar superstructure 3 and to a wall-like 2D layer 4, respectively, with concomitant modulation of the magnetic properties of 1 and 2. Thus, to each of the two levels of structural complexity generated by the two sequential self-assembly steps corresponds the emergence of novel functional features. 相似文献
39.
V. Ksenofontov S. Reiman M. Waldeck R. Niewa R. Kniep P. Gütlich 《无机化学与普通化学杂志》2003,629(10):1787-1794
The stoichiometric iron nitrides γ′‐Fe4N, ε‐Fe3N and ζ‐Fe2N were characterized by Mössbauer spectroscopy. The thermal decomposition of ε‐Fe3N was studied in‐situ by means of a specially developed Mössbauer furnace. We found ε‐Fe3N to γ′‐Fe4N and ε‐Fe3Nx (x ≥ 1.3) as decomposition products and determined the border of γ′/ε transformation at T ? 930 K. Mössbauer spectroscopy was applied to study in‐situ the thermal decomposition of the nitridometalate Li3[FeIIIN2] and the formation of Li2[(Li1‐xFeIx)N], the compound with the largest local magnetic field ever observed in an iron containing material. The kinetics of formation and the stability of Li2[(Li1‐xFeIx)N] was of particular interest in the present study. 相似文献
40.
Garcia Y Moscovici J Michalowicz A Ksenofontov V Levchenko G Bravic G Chasseau D Gütlich P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(21):4992-5000
[Fe(hyptrz)3](4-chloro-3-nitrophenylsulfonate)22 H2O (1; hyptrz=4-(3-hydroxypropyl)-1,2,4-triazole) has been synthesized and its physical properties have been investigated by several physical techniques including magnetic susceptibility measurements, calorimetry, and M?ssbauer, optical, and EXAFS spectroscopy. Compound 1 exhibits a spin transition below room temperature, together with a very wide thermal hysteresis of about 50 K. This represents the widest hysteresis loop ever observed for an FeII-1,2,4-triazole spin transition material. The cooperativity is discussed on the basis of temperature-dependent EXAFS studies and of the structural features of a CuII analogue. The EXAFS structural model of (1) in both spin states is compared to that obtained for a related material whose spin transition occurs above room temperature. EXAFS spectroscopy suggests that 1,2,4-triazole chain compounds retain a linear character whatever the spin state of the iron(II). 相似文献