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161.
Watanabe K Tanaka R Sakurai H Iguchi K Yamada Y Hsu CS Sakuma C Kikuchi H Shibayama H Kawai T 《Chemical & pharmaceutical bulletin》2007,55(5):780-783
The structure of a new monomeric peptidoglycan-related compound with hypotensive and diuretic activities, cymbidine A (1) isolated from the orchid Cymbidium goeringii, was elucidated mainly by spectroscopic analysis. The structure of 1 was shown to involve four amino acids (D-alanin, meso-diaminopimelic acid, D-gultamic acid, and L-valine) and two amino sugars (N-acetylglucosamine and 1,6-anhydro-N-acetylmuramic acid). The sequence of the amino acids and amino sugars was determined by the analysis of 2D NMR data. The absolute stereochemistries of the three amino acids (D-Ala, D-Glu and L-Val) were determined by the modified Marfey's method, and the (6S,10R) configurations of meso-diaminopimelic acid in 1 were indicated on the basis of the CD analysis. The absolute stereochemistry of 1,6-anhydro-N-acetylmuramic acid was also determined by CD data. 相似文献
162.
Yamasaki K Sakuma Y Sasaki J Matsumoto K Anzai K Matsuoka K Honda C Tsukada M Endo K Enomoto S 《Analytical and bioanalytical chemistry》2011,401(8):2531-2538
The excretion of essential trace elements, namely, Se, Sr, As, Mn, Co, V, Fe, and Zn into the bile of Se-deficient (SeD) Wistar
male rats was studied using the multitracer (MT) technique, and instrumental neutron activation analysis (INAA). Normal and
Se-control (SeC) rat groups were used as reference groups to compare the effects of Se levels on the behaviors of the essential
trace elements. The excretion (% dose) of Se, Sr, As, Mn, Co, and V increased with Se levels in the liver. The biliary excretion
of Mn and As dramatically enhanced for SeC rats compared with SeD rats, while that of V accelerated a little for SeC rats.
The radioactivity levels of 59Fe and 65Zn in the MT tracer solution were insufficient to measure their excretion into bile. The role of glutathione and bilirubin
for biliary excretion of the metals was discussed in relation to Se levels in rat liver. 相似文献
163.
S. A. Danilkin M. Avdeev T. Sakuma R. Macquart C. D. Ling M. Rusina Z. Izaola 《Ionics》2011,17(1):75-80
The paper reports the results of a neutron scattering study of Cu2 - dSe {\hbox{C}}{{\hbox{u}}_{{2 - \delta }}}{\hbox{Se}} superionic compounds. The crystallographic model fitted to the diffraction data shows the occupation of 8c and 32f sites by Cu atoms. Observed diffuse background is related to correlated thermal vibrations of Se and Cu atoms, with Se↔Cu
(8c,32f) and Cu (8c)↔Cu (8c) correlations being most important. The quasi-elastic neutron experiments show the decrease of the self-diffusion coefficient
with the deviation from the stoichiometry due to the longer residence time of Cu ions between diffusion hops. Combination
of neutron diffraction, diffuse scattering and quasi-elastic scattering experimental data suggests that the Cu atoms diffuse
between the nearest 8c sites through the 32f sites. 相似文献
164.
Y. Sakuma K. Matsuoka C. Honda K. Matsumoto K. Endo 《Journal of Radioanalytical and Nuclear Chemistry》2008,277(3):591-594
The dynamics of redox related elements (Fe, Co, Zn, and Se) were studied using instrumental neutron activation analysis as
a function of rat age in the range of 4 to 16 weeks. Activity levels of glutathione peroxidase (GSH-Px), thiobarbituric acid
reactive substance (TBARS) were assayed, and hydrogen peroxide (H2O2) concentrations were measured for the same liver homogenates using an X-band ESR spectrometer. The oxidative stress, the
aging effect, and the mineral valance are discussed. 相似文献
165.
The transcorrelated (TC) method is one of the promising wave-function-based approaches for the first-principles electronic structure calculations. In this method, the many-body wave function is approximated as the Jastrow-Slater type and one-electron orbitals in the Slater determinant are optimized with a one-body self-consistent-field equation such as that in the Hartree-Fock (HF) method. Although the TC method has yielded good results for both molecules and solids, its computational cost in solid-state calculations, being of order O(N(k)(3)N(b)(3)) with N(k) and N(b) the respective numbers of k-points and bands, has for some years hindered its wide application in condensed matter physics. Although an efficient algorithm was proposed for a Gaussian basis set, that algorithm is not applicable to a plane-wave basis that is suited to and widely used in solid-state calculations. In this paper, we present a new efficient algorithm of the TC method for the plane-wave basis or an arbitrary basis function set expanded in terms of plane waves, with which the computational cost of the TC method scales as O(N(k)(2)N(b) (2)). This is the same as that of the HF method. We applied the TC method with the new algorithm to obtain converged band structure and cell parameters of some semiconductors. 相似文献
166.
Takashi Sakuma Saumya R. Mohapatra Hiroyuki Uehara Khairul Basar Osamu Kamishima 《Journal of Non》2011,357(2):559-562
Neutron diffraction measurements have been performed on powder Ge at 6, 150 and 300 K. Oscillatory diffuse scattering intensity is clearly observed at 150 and 300 K. The diffuse scattering theory including correlation effects among thermal displacements of atoms is applied to background function in the Rietveld analysis. The inter-atomic distance and temperature dependence of the values of correlation effects are discussed. The force constants among the first, second and third nearest neighboring atoms in Ge are obtained from the values of correlation effects and Debye-Waller temperature parameters. A phonon dispersion spectrum in Λ [111] direction for Ge crystal has also been calculated at 80 K using inter-atomic force constants and the crystal structure. 相似文献
167.
Naruki M Fukao Y Funahashi H Ishino M Kanda H Kitaguchi M Mihara S Miwa K Miyashita T Murakami T Nakura T Sakuma F Togawa M Yamada S Yoshimura Y En'yo H Muto R Tabaru T Yokkaichi S Chiba J Ieiri M Sasaki O Sekimoto M Tanaka KH Hamagaki H Ozawa K 《Physical review letters》2006,96(9):092301
The invariant mass spectra of e+e- pairs produced in 12 GeV proton-induced nuclear reactions are measured at the KEK Proton Synchrotron. On the low-mass side of the meson peak, a significant enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted. 相似文献
168.
This paper investigates some properties of Euclidean distance matrices (EDMs) with focus on their ordering structure. The ordering treated here is the group majorization ordering induced by the group of permutation matrices. By using this notion, we establish two monotonicity results for EDMs: (i) The radius of a spherical Euclidean distance matrix (spherical EDM) is increasing with respect to the group majorization ordering. (ii) The larger an EDM is in terms of the group majorization ordering, the more spread out its eigenvalues are. Minimal elements with respect to this ordering are also described. 相似文献