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91.
Kristie C. Armstrong 《Talanta》2010,82(2):675-431
A bismuth bulk electrode (BiBE) has been investigated as an alternative electrode for the anodic stripping voltammetric (ASV) analysis of Pb(II), Cd(II), and Zn(II). The BiBE, which is fabricated in-house, shows results comparable to those of similar analyses at other Bi-based electrodes. Metal accumulation is achieved by holding the electrode potential at −1.4 V (vs. Ag/AgCl) for 180 s followed by a square wave voltammetric stripping scan from −1.4 to −0.35 V. Calibration plots are obtained for all three metals, individually and simultaneously, in the10-100 μg L−1 range, with a detection limit of 93, 54, and 396 ng L−1 for Pb(II), Cd(II), Zn(II), respectively. A slight reduction in slope is observed for Cd(II) and Pb(II) when the three metals are calibrated simultaneously vs. individually. Comparing the sensitivities of the metals when calibrated individually vs. in a mixture reveals that Zn(II) is not affected by stripping in a mixture. However, Pb(II) and Cd(II) have decreasing sensitivities in a mixture. The optimized method has been successfully used to test contaminated river water by standard addition. The results demonstrate the ability of the BiBE as an alternative electrode material in heavy metal analysis. 相似文献
92.
This work exploited a sequential injection lab-on-valve (LOV) system for the determination of cadmium by anodic stripping voltammetry (ASV). A miniaturized electrochemical flow cell (EFC) was fabricated in LOV, in which a nafion coated bismuth film electrode was used as working electrode. The cadmium was electrodeposited on the electrode surface in bismuth solution, and measured with the subsequential stripping scan. Under optimal conditions, the proposed system responded linearly to cadmium concentrations in a range 2.0-100.0 μg L−1. The detection limit of this method was found to be 0.88 μg L−1. By loading a sample volume of 800 μL, a sampling frequency of 22 determinations h−1 was achieved. The repeatability expressed as relative standard derivation (R.S.D.) was 3.65% for 20 μg L−1 cadmium (n = 11). The established method was applied to analysis of trace cadmium in environmental water samples and the spiked recoveries were satisfactory. 相似文献
93.
Bright red crystals of [Mn(H2O)6][BiI4]2 · 2H2O are obtained from a solution of MnI2, BiI3, and I2 in absolute ethanol, which is exposed to humid air. Reversible dehydratization sets in at about 50 °C. Added water decomposes the hydrate by irreversible precipitation of BiOI. The optical bandgap is about 1.9(1) eV. X‐ray diffraction on a single‐crystal revealed a monoclinic lattice (space group P21/c) with a = 760.39(4) pm, b = 1315.6(1) pm, c = 1398.37(7) pm, and β = 97.438(4)°. In the crystal structure zigzag chains of edge‐sharing [BiI2/1I4/2]– octahedra and linear strings of H2O‐bridged [Mn(H2O)6]2+ octahedra run parallel [100]. 相似文献
94.
Three novel sandwich‐type polyoxotungstates ( 1 – 3 ) were synthesized in good yield using an in‐situ conventional solution synthesis method by reaction in aqueous media below 80 °C. Compounds 1 – 3 represent the first structurally characterized β‐B‐BiW9 sandwich‐type polyoxometalates with triethanolamine cations. All three compounds have the same building unit [(X(H2O)3)2(X0.5W0.5O)2(β‐B‐BiW9O33)2)]10– [X = MnII ( 1 ), CoII ( 2 ), NiII ( 3 )]. The adjacent units of 1 or 2 are joined by Na+ cations in different ways to construct 1D chains or 2D sheets. A 3D supramolecular structure is further formed by hydrogen bond interactions among water molecules and protonated triethanolamine cations. Meanwhile only compound 3 shows a 0D structure. The compounds were characterized by elemental analysis, IR spectroscopy, TG analysis, and single‐crystal X‐ray diffraction. Magnetic measurements on a sample of 1 show the presence of paramagnetic interactions. 相似文献
95.
Wenlong Yin Dajiang Mei Jiyong Yao Peizhen Fu Yicheng Wu 《Journal of solid state chemistry》2010,183(11):2544-2551
Two new ternary bismuth chalcogenides, Bi3In4S10 and Bi14.7In11.3S38, were synthesized from the reactions of binary sulfides via a two-step flux technique. Single-crystal X-ray diffraction analyses indicate that Bi3In4S10 crystallizes in the non-centrosymmetric space group Pm and Bi14.7In11.3S38 crystallizes in the centrosymmetric space group P21/m. Both compounds adopt three-dimensional frameworks. A distinct structural feature in the two structures is the presence of chains of Bi atoms with alternating short Bi-Bi bonds of around 3.1 Å and longer distances of around 4.6 Å. The optical band gaps of 1.42(2) eV for Bi3In4S10 and 1.45(2) eV for Bi14.7In11.3S38 were deduced from the diffuse reflectance spectra. 相似文献
96.
Dajiang Mei Zheshuai Lin Jiyong Yao Peizhen Fu 《Journal of solid state chemistry》2010,183(7):1640-2985
Two new bismuth sulfides KBiSiS4 and KBiGeS4 have been synthesized by means of the reactive flux method. They adopt the RbBiSiS4 structure type and crystallize in space group P21/c of the monoclinic system. The structure consists of (M=Si, Ge) layers separated by bicapped trigonal-prismatically coordinated K atoms. The M atom is tetrahedrally coordinated to four S atoms and the Bi atom is coordinated to a distorted monocapped trigonal prism of seven S atoms. The optical band gap of 2.25(2) eV for KBiSiS4 was deduced from the diffuse reflectance spectrum. From a band structure calculation, the optical absorption for KBiSiS4 originates from the layer. The Si 3p orbitals, Bi 6p orbitals, and S 3p orbitals are highly hybridized near the Fermi level. The orbitals of K have no contributions on both the upper of valence band and the bottom of conduction band. 相似文献
97.
Series of compositions Bi2(M′xM1−x)4O9 with x=0.0, 0.1,…, 1.0 and M′/M=Ga/Al, Fe/Al and Fe/Ga were synthesized by dissolving appropriate amounts of corresponding metal nitrate hydrates in glycerine, followed by gelation, calcination and final heating at 800 °C for 24 h. The new compositions with M′/M=Ga/Al form solid-solution series, which are isotypes to the two other series M′/M=Fe/Al and Fe/Ga. The XRD data analysis yielded in all cases a linear dependence of the lattice parameters related on x. Rietveld structure refinements of the XRD patterns of the new compounds, Bi2(GaxAl1−x)4O9 reveal a preferential occupation of Ga in tetrahedral site (4 h). The IR absorption spectra measured between 50 and 4000 cm−1 of all systems show systematic shifts in peak positions related to the degree of substitution. Samples treated in 18O2 atmosphere (16 h at 800 °C, 200 mbar, 95% 18O2) for 18O/16O isotope exchange experiments show a well-separated IR absorption peak related to the M-18Oc-M vibration, where Oc denotes the common oxygen of two tetrahedral type MO4 units. The intensity ratio of M-18Oc/M-16Oc IR absorption peaks and the average crystal sizes were used to estimate the tracer diffusion coefficients of polycrystalline Bi2Al4O9 (D=2×10−22 m2s−1), Bi2Fe4O9 (D=5×10−21 m2s−1), Bi2(Ga/Al)4O9 (D=2×10−21 m2s−1) and Bi2Ga4O9 (D=2×10−20 m2s−1). 相似文献
98.
99.
(WO3)0.15(BiO1.5)0.85 exhibits a tetragonal structure derived from the fluorite subcell. The electrical conductivity of (WO3)0.15(BiO1.5)0.85 is lower than that of Y2O3-doped Bi2O3. The structure and electrical conductivity of samples formulated as (YO1.5)
x
(WO3)0.15(BiO1.5)0.85-
x
(x = 0.1, 0.2, 0.3, and 0.4) were investigated. The as-sintered (YO1.5)0.1(WO3)0.15(BiO1.5)0.75 exhibited a single cubic structure that is isostructural with δ-Bi2O3. For x = 0.2, 0.3, and 0.4, the as-sintered samples consisted of a cubic fluorite structure and rhombohedral Y6WO12. After heat treatment at 600 °C for 200 h, the cubic structures are stable for x = 0.1, 0.3, and 0.4. A transformation from cubic to rhombohedral phase after heat treatment at 600 °C for 200 h was observed
in the sample originally formulated as (YO1.5)0.2(WO3)0.15(BiO1.5)0.65. 相似文献
100.