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901.
Comparative Studies on Chemical Modification by Diethyldithiocarbamate for ETV-ICP-OES and ETAAS Determination of Chromium and Nickel 总被引:1,自引:0,他引:1
The chemical modification of diethyldithiocarbamate (DDTC) in electrothermal vaporization inductively coupled plasma optical
emission spectrometry (ETV-ICP-OES) and in electrothermal atomic absorption spectrometry (ETAAS) was comparatively investigated.
The experimental results indicated that the formation of Cr- and Ni-DDTC chelates enhanced significantly the emission signals
of Cr and Ni in ETV-ICP-OES, but decreased the absorption signal of Cr and Ni in ETAAS. The different role of DDTC in ETV-ICP-OES
and ETAAS was attributed to the different functions of the graphite furnace in the two techniques. The graphite furnace was
used as both a vaporizer and an atom-vessel for analytes in ETAAS, but only used as a vaporizer for the sample in ETV-ICP-OES.
Thermal gravimetric analysis of Cr- and Ni-DDTC chelates and UV-Vis analysis of the sample vapor collected in CHCl3 after vaporization of their chelates from the graphite furnace indicated that the analytes were vaporized and transported
into ICP as their chelates. In addition, the vaporization mechanism of Cr and Ni was also briefly discussed. 相似文献
902.
903.
Marcela Stoia C. Caizer M. Stefanescu P. Barvinschi I. Julean 《Journal of Thermal Analysis and Calorimetry》2007,88(1):193-200
This article presents the results
of our investigation on the obtaining of Ni0.65Zn0.35Fe2O4 ferrite nanoparticles embedded in a SiO2 matrix using
a modified sol–gel synthesis method, starting from tetraethylorthosilicate
(TEOS), metal (FeIII,NiII,ZnII)
nitrates and ethylene glycol (EG). This method consists in the formation of
carboxylate type complexes, inside the silica matrix, used as forerunners
for the ferrite/silica nanocomposites. We prepared gels with different compositions,
in order to obtain, through a suitable thermal treatment, the nanocomposites
(Ni0.65Zn0.35Fe2O4)x–(SiO2)100–x (where x=10,
20, 30, 40, 50, 60 mass%). The synthesized gels were studied by differential
thermal analysis (DTA), thermogravimetry (TG) and FTIR spectroscopy.
The formation of Ni–Zn ferrite in the silica matrix and the behavior
in an external magnetic field were studied by X-ray diffraction (XRD) and
quasi-static magnetic measurements (50 Hz). 相似文献
904.
M. Lalia-Kantouri M. Hartophylles P. D. Jannakoudakis G. P. Voutsas 《无机化学与普通化学杂志》1995,621(4):645-653
The reaction products of five 2-hydroxyaryloximes with Ni(II), Pd(II), and Co(II) have been obtained and characterized by elemental analyses, conductometric measurements, magnetic moment determination, and spectroscopic methods (IR, 1H NMR, electronic absorption in solutions and in solid state). Cyclic voltammetry on mercury and carbon fibre electrodes has been employed to investigate the electrochemical behaviour in DMF solutions. The effect of substituents on the structure of the chelates and the electron distribution is assessed, discussed and compared with the behaviour of the corresponding copper(II) chelates. The structure of the title compound trans-bis(propanone, 1-[2-hydroxyphenyl]-oximato) nickel(II), Ni(C9H10NO2)2 was determined by X-ray diffraction monoclinic system (space group P21/n), a = 11.894, b = 5.126, c = 13.668 Å, b? = 103.72°, Z = 2. The structure was refined by full-matrix least squares to a conventional R = 0.03. Ni is on the equatorial plane and surrounded by two nitrogen and two oxygen at distances 1.884(3) Å and 1.825(2) Å, respectively. 相似文献
905.
Theoretical study of magnetic coupling interaction in terephthalato‐bridged Ni(II) binuclear systems
The density functional theory combined with broken‐symmetry approach has been successfully extended into the study of the long‐range weak coupling interaction in a binuclear Ni(II) complex bridged by terephthalate dianion. The calculated magnetic coupling constant (?0.27 cm?1) is well in agreement with the experimental one (?0.33 cm?1). The relative magnitude of the energies of different spin states has been obtained. The spin delocalization and spin polarization occur between two Ni(II) ions, based on the analysis of the spin density distribution. Weak antiferromagnetic behavior in such a system may result from the competition between spin delocalization and spin polarization where the former is dominant. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004 相似文献
906.
The dissociation constants for o-carboxyphenylhydrazoethylacetoacetate (o-CPHEA) ligand, as well as the stability constants for the divalent metal complexes of Cu, (II), Ni (II), Co (II), Zn (II)and Cd (II) ions, have been calculated pH-meterically in different solvents. The dissociation constans pK1=4.10 and pK2=10.55 of the insoluble organic ligand are calculated in aqueous medium. The effect of solvents, the relation between stabilities and both electronegativities and ionization potential are studied. 相似文献
907.
含有氨基酸基Schiff碱配体的锌、镍配合物的合成、结构及热分解动力学研究 总被引:2,自引:0,他引:2
合成了2种含有水杨醛氨基乙酸类(Schiff碱)配体的配合物: (C9H7NO3)Zn(C3H4N2)2(1)和(C9H7NO3)Ni(C3H4N2)2(C4H5N2O)•CH3OH•0.5H2O(2), 其中配合物(1)能够在激发波长为260 nm的条件下发出很强的蓝光. 相似文献
908.
L. A. Glinskaya T. G. Leonova T. E. Kokina R. F. Klevtsova S. V. Larionov 《Journal of Structural Chemistry》2005,46(4):692-698
Crystal structures of chelate compounds Ni[(iso-C4H9)2PS2]2 (I) and Pd[(iso-C4H9)2PS2]2 (II) have been determined by X-ray diffraction: diffractometer X8-APEX, MoK
α∔
-radiation, 1048 F
hkl
, R = 0.0544 for I and CAD-4 diffractometer, MoK
α∔
-radiation, 1283 F
hkl
, R = 0.0347 for II. The crystals are rhombic: a = 12.921(5) Å, b = 17.094(5) Å, c = 22.971(5) Å; V = 5074(3) Å3, Z = 8, calc = 1.250 g/cm3, space group Pbca for I and a = 13.312(3) Å, b = 16.130(7) Å, c = 23.171(5) Å; V = 4975(3) Å3, Z = 8, ρcalc = 1. 208 g/cm3, space group Pbca for II. The structures of I and II are formed by discrete mononuclear molecules. Coordination cores MS4 (M = Ni, Pd) approach planar square configurations.
Original Russian Text Copyright ? 2005 by L. A. Glinskaya, T. G. Leonova, T. E. Kokina, R. F. Klevtsova, and S. V. Larionov
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 4, pp. 715–720, July–August, 2005. 相似文献
909.
Cloud Point Preconcentration and Flame Atomic Absorption Spectrometric Determination of Cobalt and Nickel in Water Samples 总被引:2,自引:0,他引:2
Cloud point methodology was successfully used to preconcentrate trace amounts of Co and Ni as a prior step to their determination
by flame atomic absorption spectrometry. 1-Nitroso-2-naphthol and polyethylene glycol-p-nonylphenylether (PONPE 7.5) are used
as hydrophobic ligand and nonionic surfactant, respectively. Optimization was performed of the variables effecting complexation
and phase separation. Additionally, the influence of viscosity on the analytical signal was investigated. Under the experimental
conditions used, preconcentration of only 10 mL of sample in the presence of 0.075% (v/v) PONPE 7.5 permitted the detection
of 1.09 μg L−1 of Ni and 1.22 μg L−1 of Co with enhancement factors of 29 and 27 for Ni and Co, respectively. The relative standard deviations (n=5) at concentrations of 80 and 50 μg L−1 for Co and Ni were 2.53 and 2.89%, respectively. Good recoveries in the range of 96–105% were obtained for spiked samples.
The effect of different interferent species was studied. The proposed method was applied to the determination of Ni and Co
in different water samples.
Correspondence: Department of Analytical Chemistry, Faculty of Chemistry, Tabriz University, Tabriz, Iran. e-mail: manzoori@tabrizu.ac.ir
Received September 1, 2002; accepted November 8, 2002 相似文献
910.