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11.
Goryunov E. I. Petrovskii P. V. Shcherbina T. M. Zakharov L. S. 《Russian Chemical Bulletin》2001,50(6):1085-1087
Catalytic phosphorylation of -trifluoromethylbenzyl alcohols with POCl3 taken in a ratio of 3 : 1 under particular temperature conditions afforded predominantly symmetrical tris(-trifluoromethylbenzyl) phosphates. The latter were obtained as mixtures of two diastereomers with a statistical ratio of the components. 相似文献
12.
A family of layered bismuth oxyhalides, LI0.5Bi1.5O2X and LIIBiO2X has been reinvestigated. Formation of X1-type Sillén compounds has been established for LI=Li, Na, LII=Ca, Sr, Ba, and X=Cl, Br, I, but the details of their crystal structures are different. While all LI0.5Bi1.5O2X, CaBiO2Br, and CaBiO2I adopt the disordered tetragonal Nd2O2Te structure, all compounds of LII=Sr and Ba are orthorhombic and isostructural to PbSbO2Cl, due to L/Bi cation ordering. Crystal structures have been determined for CaBiO2I, SrBiO2Br, SrBiO2I, and BaBiO2I. We discuss the factors which determine the occurrence and type of cation ordering in the quaternary bismuth and antimony X1-type oxyhalides. We also predict that more isostructural compounds can be prepared with antimony. 相似文献
13.
The epoxy-impregnated graphite tube electrode bulk modified with 2-mercaptobenzoxazole, employed in a wall-jet configuration, was found to be useful for the continuous flow and flow injection stripping voltammetric determinations of AgI, HgII and BiIII. For continuous flow, detection limits for AgI, HgII and BiIII were 1.8 × 10−10 M, 1.9 × 10−9 M and 9.5 × 10−9 M, respectively (10 min accumulation, S/N = 3). Precisions for 5.00 × 10−9 M AgI, 1.00 × 10−8 M HgII and 1.00 × 10−7 M BiIII were 10.5%, 5.77 % and 7.90% (relative standard deviations, n = 6), respectively. In the case of flow injection stripping, with a 500 μL injection loop, detection limits of 0.59 ng, 2.0 ng and 120 ng were obtained for AgI, HgII and BiIII, respectively (S/N = 3). Selected metal ions, inorganic and organic substances were investigated for interferences. The electrode was tested with a certified sample and then applied to the determinations of the metal ions in a urine and a sea-water sample. 相似文献
14.
Korolczuk M Moroziewicz A Grabarczyk M 《Analytical and bioanalytical chemistry》2005,382(7):1678-1682
Procedures for trace cobalt determinations by adsorptive stripping voltammetry at in situ and ex situ plated bismuth film electrodes are presented. These exploit the enhancement of the cobalt peak obtained by using the Co(II)–dimethylglyoxime–cetyltrimethylammonium bromide–piperazine-N,N-bis(2-ethanesulfonic acid) system. The calibration graph for an accumulation time of 120 s was linear from 2 × 10–10 to 2 × 10–8 mol L–1. The relative standard deviation from five determinations of cobalt at a concentration of 5 × 10–9 mol L–1 was 5.2%. The detection limit for an accumulation time of 300 s was 1.8 × 10–11 mol L–1. The proposed procedure was applied to cobalt determination in certified reference materials and in tap and river water samples. 相似文献
15.
16.
Banks CE Kruusma J Hyde ME Salimi A Compton RG 《Analytical and bioanalytical chemistry》2004,379(2):277-282
Bismuth-modified glassy carbon electrodes have been investigated for their suitability in sonoelectroanalysis. The stability of the bismuth film to the application of ultrasound was assessed via voltammetric and atomic force microscopy (AFM) studies which revealed little ablation at powers up to an intensity of 130 W cm–2 delivered from a 25-kHz sonic horn. Furthermore, bismuth-film-modified glassy carbon electrodes were evaluated for the sonoelectroanalytical quantification of zinc and cadmium. Detection limits of 2×10–7 M and 6×10–9 M respectively were found after a 60-s deposition time via an acoustically assisted deposition protocol. 相似文献
17.
18.
F. Mauvy 《Journal of solid state chemistry》2005,178(6):2015-2023
The two hitherto unknown compounds Bi14P4O31 and Bi50V4O85 were prepared by the direct solid-state reaction of Bi2O3 and (NH4)H2PO4 or V2O5, respectively. Bi14P4O31 crystallizes in a C-centred monoclinic symmetry (C2/c space group) with the unit-cell parameters: , , and β=93.63(1)° (Z=16). The symmetry of Bi50V4O85 is also monoclinic (I2/m space group) with lattice parameters of , , and β=90.14(1)° (Z=2). Both structures correspond to a fluorite-type superstructure where the Bi and P or V atoms are ordered in the framework. An idealized structural model is proposed where the structures result of the stacking of mixed atomic layers of composition [Bi14M4O31] and [Bi18O27] respectively. This new family can be formulated Bi18−4mM4mO27+4m with M=P, V and where the parameter m (0?m?1) represents the ratio of the number of [Bi14M4O31] layers to the total number of layers in the sequence. Bi14P4O31 corresponds to m=1 when Bi50V8O85 corresponds to m=1/3. In this last case, the structural sequence is simply one [Bi14V4O31] layer to two [Bi18O27] layers. As predicted by the proposed structural building principle, Bi14P4O31 is not a good ionic conductor. The conductivity at 650 °C is 4 orders of magnitude lower from those found in Bi46M8O89 (M=P, V) (m=2/3) and Bi50V4O85 (m=1/3). 相似文献
19.
The preconcentration and voltammetric behavior of BiIII on a sodium humate modified carbon paste electrode was studied by means of cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV). The proposed measurement involves an initial nonelectrolytic preconcentration step in which BiIII is complexed by the surface modifier in a solution of 0.05 M KNO3-0.0106 M HNO3 (pH 2.0) and a subsequent electrochemical scan step in which the preconcentrated BiIII was reduced and then oxidized promptly in supporting electrolyte of 0.5 M HNO3. The resulting DPSV anodic current was proportional to the concentration of BiIII ion over the range of 4.78 × 10−8–1.44 × 10−5 M. The detection limit was 4.78 × 10−8 M. The proposed method was used to determine bismuth in various samples. Various factors affecting the electrode behavior were also investigated at the same time. 相似文献
20.
Nanocomposite polymers containing bismuth nanoparticles (2 wt%) have been obtained by photopolymerization of acrylic resins. The bismuth nanoparticles have been synthesized by reduction of BiCl3 with t-BuONa activated sodium hydride. In situ t-BuONa stabilization protects the metallic particles against aggregation. Transmission electron microscopy (TEM) analysis has shown that the bismuth nanoparticles are well dispersed in the acrylic resin. The curing process was followed quantitatively by infrared spectroscopy through the decrease upon UV exposure of the IR bands characteristic of the functional groups. The bismuth nanoparticles were found to have no detrimental effect on the photopolymerization kinetics. Dynamic mechanical analysis (DMA) has shown that the viscoelastic properties of the nanocomposite photopolymer are significantly modified in comparison with corresponding UV-cured polymer. The addition of metal nanoparticles was found to greatly reduce the gloss of UV-cured coatings. 相似文献