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71.
Soluble luminescent complexes of divalent lanthanides, LnCl2·xTHF (Ln = Eu, Yb, and Sm), were obtained for the first time by reduction of LnIII to LnII in reactions of the lanthanide trichloride hexahydrates LnCl3·6H2O with Bui 2AlH in THF. The photoluminescence spectra and other spectral characteristics of LnCl2·xTHF were examined. 相似文献
72.
Vladimir P. Zaytsev Fedor I. Zubkov Flavien A. A. Toze Daria N. Orlova Maria N. Eliseeva Dmitry G. Grudinin Eugeniya V. Nikitina Alexey V. Varlamov 《Journal of heterocyclic chemistry》2013,50(Z1):E18-E38
The interactions between 4‐R‐substituted 2‐furyl‐1,2,3,4‐tetrahydroquinolines (synthesized by the Povarov reaction) and a number of alkenes have been investigated. Maleic, dibromomaleic, dichloromaleic, and citraconic anhydrides, as well as acryloyl, methacryloyl, crotonyl, and cynnamoyl chlorides were used as alkene components. It was shown that the initial N‐acylation of the tetrahydroquinolines was followed by a spontaneous [4+2]‐cycloaddition of an N‐acryloyl substituent to the furan ring. It was established that the intramolecular Diels–Alder reaction of furans is reversible, occurs stereoselectively as exo‐addition, and led to target epoxyisoindolo[2,1‐a]tetrahydroquinolines with moderate yields. Oxidation and aromatization of the synthesized products were carried out. 相似文献
73.
I. P. Malkerova A. S. Alikhanyan S. V. Eliseeva V. A. Ketsko N. P. Kuz’mina 《Russian Journal of Inorganic Chemistry》2007,52(6):918-921
The thermal behavior and thermodynamic properties of europium tris(hexafluoroacetylacetonate) Eu(hfa)3 and the mixed-ligand 4-cyanopyridine-N-oxide complex [Eu(hfa)3(cpo)] were investigated by thermal analysis and Knudsen effusion mass spectrometry. The compounds sublime congruently. The composition of the gas phase over the compounds and the partial pressures of the components were determined. The enthalpies of sublimation, polymerization, and dissociation of these compounds were derived from experimental data. 相似文献
74.
The causes of a high total conversion and the S-shaped pattern of the time dependence of conversion for copper sol-catalyzed hydrolysis of the lactam rings of poly(N-vinylpyrrolidone) have been studied. The high conversion of the hydrolusis is achieved via replacement of modified macromolecules in shields of catalyst particles with less modified macromolecules from the dispersion medium of a sol in the course of reaction owing to a decline in the stability of copper nanoparticle complexes with macromolecules with an increase in the degree of hydrolysis. A reduction in the complex stability leads to an increase in the lability of bonding of shielding polymer chains with the catalyst surface and to the growth of the rate of rearrangement and the overall rate of reaction after the induction period. This situation is also responsible for the enlargement of nanosized catalyst particles in the course of reaction and the destruction of the sol after a limiting conversion of units of ~40–50% is attained. 相似文献
75.
Dehaen G Verwilst P Eliseeva SV Laurent S Vander Elst L Muller RN De Borggraeve WM Binnemans K Parac-Vogt TN 《Inorganic chemistry》2011,50(20):10005-10014
Trinuclear heterobimetallic Ln(III)-Ru(II) complexes (Ln = Eu, Gd) based on a 1,10-phenanthroline ligand bearing a diethylenetriaminepentaacetic acid (DTPA) core have been synthesized and fully characterized by a range of experimental techniques. The (17)O NMR and proton nuclear magnetic relaxation dispersion (NMRD) measurements of Gd(III)-Ru(II) show that, in comparison to the parent Gd-DTPA, this complex exhibits improved relaxivity, which is the result of an increase of the rotational correlation time. Relaxometry and ultrafiltration experiments indicate that the 1,10-phenanthroline ligand has a high affinity for noncovalent binding to human serum albumin, which results in a high relaxivity r(1) of 14.3 s(-1) mM(-1) at 20 MHz and 37 °C. Furthermore, the Ln(III)-Ru(II) complexes (Ln = Eu, Gd) show an intense light absorption in the visible spectral region due to metal-to-ligand charge transfer (MLCT) transitions. Upon excitation into the MLCT band at 440 nm, the complexes exhibit a bright-red luminescence centered at 610 nm, with a quantum yield of 4.7%. The luminescence lifetime equals 540 ns and is therefore long enough to exceed the fluorescent background. Monometallic lanthanide complexes have also been synthesized, and the Eu(III) analogue shows a characteristic red luminescence with a quantum yield of 0.8%. Taking into account the relaxometric and luminescent properties, the developed Gd(III)-Ru(II) complex can be considered as a potential in vitro bimodal imaging agent. 相似文献
76.
Cardinaels T Lava K Goossens K Eliseeva SV Binnemans K 《Langmuir : the ACS journal of surfaces and colloids》2011,27(5):2036-2043
The 1,10-phenanthrolinium cation is introduced as a new building block for the design of ionic liquid crystals. 1,10-Phenanthroline, 5-methyl-1,10-phenanthroline, 5-chloro-1,10-phenanthroline, and 4,7-diphenyl-1,10-phenanthroline were quaternized by reaction with 1,3-dibromopropane or 1,2-dibromoethane. The resulting cations were combined with dodecyl sulfate or dioctyl sulfosuccinate anions. The influence of both the cation and anion type on the thermal behavior was investigated. Several of the complexes exhibit mesomorphic behavior, with smectic E phases for the dodecyl sulfate salts and smectic A phases for the dioctyl sulfosuccinate salts. Structural models for the packing of the 1,10-phenanthrolinium and anionic moieties in the liquid-crystalline phases are presented. The ionic compounds show fluorescence in the solid state and in solution. 相似文献
77.
E Debroye G Dehaen SV Eliseeva S Laurent L Vander Elst RN Muller K Binnemans TN Parac-Vogt 《Dalton transactions (Cambridge, England : 2003)》2012,41(35):10549-10556
A ditopic DTPA monoamide derivative containing an 8-hydroxyquinoline moiety was synthesized and the corresponding gadolinium(iii) complex ([Gd(H5)(H(2)O)](-)) was prepared. After adding aluminum(iii), the 8-hydroxyquinoline part self-assembled into a heteropolymetallic triscomplex [(Gd5)(3)Al(H(2)O)(3)](3-). The magnetic and optical properties of this metallostar compound were investigated in order to classify it as a potential in vitro bimodal contrast agent. The proton nuclear magnetic relaxation dispersion measurements indicated that the relaxivity r(1) of [Gd(H5)(H(2)O)](-) and [(Gd5)(3)Al(H(2)O)(3)](3-) at 20 MHz and 310 K equaled 6.17 s(-1) mM(-1) and 10.9 s(-1) mM(-1) per Gd(iii) ion respectively. This corresponds to a relaxivity value of 32.7 s(-1) mM(-1) for the supramolecular complex containing three Gd(iii) ions. The high relaxivity value is prominently caused by an increase of the rotational tumbling time τ(R) by a factor of 2.7 and 5.5 respectively, in comparison with the commercially used MRI contrast agent Gd(iii)-DTPA (Magnevist?). Furthermore, upon UV irradiation, [(Gd5)(3)Al(H(2)O)(3)](3-) exposes green broad-band emission with a maximum at 543 nm. Regarding the high relaxivity and the photophysical properties of the [(Gd5)(3)Al(H(2)O)(3)](3-) metallostar compound, it can be considered as a lead compound for in vitro bimodal applications. 相似文献
78.
Aboshyan-Sorgho L Nozary H Aebischer A Bünzli JC Morgantini PY Kittilstved KR Hauser A Eliseeva SV Petoud S Piguet C 《Journal of the American Chemical Society》2012,134(30):12675-12684
This work illustrates a simple approach for optimizing long-lived near-infrared lanthanide-centered luminescence using trivalent chromium chromophores as sensitizers. Reactions of the segmental ligand L2 with stoichiometric amounts of M(CF(3)SO(3))(2) (M = Cr, Zn) and Ln(CF(3)SO(3))(3) (Ln = Nd, Er, Yb) under aerobic conditions quantitatively yield the D(3)-symmetrical trinuclear [MLnM(L2)(3)](CF(3)SO(3))(n) complexes (M = Zn, n = 7; M = Cr, n = 9), in which the central lanthanide activator is sandwiched between the two transition metal cations. Visible or NIR irradiation of the peripheral Cr(III) chromophores in [CrLnCr(L2)(3)](9+) induces rate-limiting intramolecular intermetallic Cr→Ln energy transfer processes (Ln = Nd, Er, Yb), which eventually produces lanthanide-centered near-infrared (NIR) or IR emission with apparent lifetimes within the millisecond range. As compared to the parent dinuclear complexes [CrLn(L1)(3)](6+), the connection of a second strong-field [CrN(6)] sensitizer in [CrLnCr(L2)(3)](9+) significantly enhances the emission intensity without perturbing the kinetic regime. This work opens novel exciting photophysical perspectives via the buildup of non-negligible population densities for the long-lived doubly excited state [Cr*LnCr*(L2)(3)](9+) under reasonable pumping powers. 相似文献
79.
A. S. Fedorov A. A. Kuzubov T. A. Kozhevnikova N. S. Eliseeva N. G. Galkin S. G. Ovchinnikov A. A. Saranin A. V. Latyshev 《JETP Letters》2012,95(1):20-24
The electronic, geometric, and magnetic structure of nanofilms of the β phase of iron disilicide FeSi2 with the (001), (100), and (010) surfaces have been simulated through density functional calculations. A substantial reconstruction
of the (001) surface terminated with silicon atoms has been observed, which was accompanied by an increase in the surface
symmetry and appearance of “squares” of silicon atoms. Analysis of the electron density of states (DOS) and spin DOS projected
on the contributions of layers of atoms (LSDOS) indicates that all plates have metallic properties. The main contribution
near the Fermi level comes from the surface iron layers and it decreases rapidly with an increase in the distance from the
surface of the plate. Analysis of the calculated effective magnetic moments of atoms shows that the surface layers in the
plates have a significant magnetic moment, in particular, iron layers on the (001) surface (1.89 μB/atom). The moments of atoms decrease rapidly with an increase in their distance from the surface. The electron and geometric
regions of a (001)Si/FeSi2 interface have been studied. Analysis of the LSDOS shows that the surface conducting state mainly determined by the contribution
from the near-surface silicide layers is implemented in this region. The possibility of the formation of the perfect and sharp
Si/FeSi2 interface has been demonstrated. 相似文献
80.
E. V. Krisilova T. V. Eliseeva V. F. Selemenev 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(11):1954-1956
The hydration of cation exchange membranes after sorption of basic amino acids was estimated by the isopiestic method. A correlation
between the length of the amino acid side group and the amount of water absorbed was observed. The influence of the number
of methylene amino acid units on the molal sorbate concentration in the membrane phase was considered. The hydration of the
membrane was compared with that of the granular ion exchanger from which it was prepared. 相似文献