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41.
Jessica A. Sigrist James D.S. Walker John R. Hayes Michael W. Gaultois Andrew P. Grosvenor 《Solid State Sciences》2011,13(11):2041-2048
The ternary, rare-earth filled (RE) Skutterudites (REM4Pn12; M = Fe–Os; Pn = P–Sb) have been proposed for use in high-temperature thermoelectric devices to convert waste heat to useful power. CeFe4Sb12 has been one of the most popular materials proposed for this application; however, it oxidizes at relatively low temperatures. The thermal stability of Skutterudites can be enhanced by selective substitution of the constituent elements and Eu(Fe,Ru)4Sb12 variants have been found to oxidize at temperatures above that of CeFe4Sb12. Unfortunately, these materials have poor thermoelectric properties. In this study, the thermal stability of CeFe4−xRuxSb12 was examined depending on the value of x. (These compounds have similar thermoelectric properties to those of CeFe4Sb12.) It has been found by use of TGA and XANES that the temperature at which point CeFe4−xRuxSb12 oxidizes increases with greater Ru substitution. XANES was also used to confirm the general charge assignment of Ce3+Fe4−x2+Rux2+Sb121−. 相似文献
42.
43.
Antibodies and antigen binding fragments thereof were photochemically immobilized on surface-modified silicon chips of 5 × 5 mm size. Silicon surface-grafted diazirines and benzophenones formed covalent bonds with the immunoreagents on light activation. Photolithographic immobilization of monoclonal antibodies in aqueous media was achieved on silicon chips by activating surface-grafted benzophenones. The presence of bovine serum albumin during irradiation reduced nonspecific adsorption of the immunoreagents and retained the immunoactivity of the photoimmobilized molecules. 相似文献
44.
45.
Auerswald J Widmer D de Rooij NF Sigrist A Staubli T Stöckli T Knapp HF 《Electrophoresis》2005,26(19):3697-3705
The use of probe beads for lab-on-chip affinity assays is very interesting from a practical point of view. It is easier to handle and trap beads than molecules in microfluidic systems. We present a method for the immobilization of probe beads at defined areas on a chip using dielectrophoresis (DEP)-controlled adhesion. The method is fast, i.e., it takes between 10 and 120 s--depending on the protocol--to functionalize a chip surface at defined areas. The method is versatile, i.e., it works for beads with different types of probe molecule coatings. The immobilization is irreversible, i.e., the retained beads are able to withstand high flow velocities in a flow-through device even after the DEP voltage is turned off, thus allowing the use of conventional high-conductivity analyte buffers in the following assay procedure. We demonstrate the on-chip immobilization of fluorescent beads coated with biotin, protein A, and goat-antimouse immunoglobulin G (IgG). The number of immobilized beads at an electrode array can be determined from their fluorescence signal. Further, we use this method to demonstrate the detection of streptavidin and mouse IgG. Finally, we demonstrate the feasibility of the parallel detection of different analyte molecules on the same chip. 相似文献
46.
It is shown that the 2-(hydroxymethyl)-1-methylazulenes 6 are being oxidized by activated MnO2 in CH2Cl2 at room temperature to the corresponding azulene-1,2-dicarbaldehydes 7 (Scheme 2). Extension of the MnO2 oxidation reaction to 1-methyl- and/or 3-methyl-substituted azulenes led to the formation of the corresponding azulene-1-carbaldehydes in excellent yields (Scheme 3). The reaction of unsymmetrically substituted 1,3-dimethyl-azulenes (cf. 15 in Scheme 4) with MnO2 shows only little chemoselectivity. However, the observed ratio of the formed constitutionally isometric azulene-1-carbaldehydes is in agreement with the size of the orbital coefficients in the HOMO of the azulenes. The reaction of guaiazulene ( 18 ) with MnO2 in dioxane/H2O at room temperature gave mainly the expected carbaldehyde 19 . However, it was accompanied by the azulene-diones 20 and 21 (Scheme 5). The precursor of the demethylated compound 20 is the carbaldehyde 19 . Similarly, the MnO2 reaction of 7-isopropyl-4-methyalazulene ( 22 ) as well as of 4,6,8-trimethylazulene ( 24 ) led to the formation of a mixture of the corresponding azulene-1,5-diones and azulene-1,7-diones 20 / 23 and 25 / 26 , respectively, in decent yields (Schemes 6 and 7). No MnO2 reaction was observed with 5,7-dimethylazulene. 相似文献
47.
M. Gianella J. M. Rey D. Hahnloser M. W. Sigrist 《The European physical journal. Special topics》2008,153(1):459-462
Smoke samples produced by colorectral laparoscopic
operations have been studied with a 13CO2 laser-based
photoacoustic spectrometer. The most difficult problem was the existence of
almost 100% CO2 present in the sample. The PA measurements were
complemented with broad range FTIR spectra. An important result is the
striking difference between sample spectra taken from different operations
and patients. Apart from dominating CO2, a first spectral analysis
revealed the existence of ~100 ppm water vapor and of unknown
compounds that could not yet be identified but that are not identical with
compounds found in related studies. 相似文献
48.
Ying-Fen Ran Martin Steinmann Marc Sigrist Shi-Xia Liu Jürg Hauser Silvio Decurtins 《Comptes Rendus Chimie》2012,15(10):838-844
The explorative lanthanide coordination chemistry of 4′,5′-bis-(propylthio)tetrathiafulvenyl[i]dipyrido[3,2-a:2′,3′-c]phenazine (TTF-dppz) is described. Thereby, four new Ln(III) complexes, [Ln(NO3)3(TTF-dppz)2] with Ln(III) = Nd (1), Eu (2), Gd (3), Tb (4), have been prepared and characterized. An X-ray crystallographic study of [Gd(NO3)3(TTF-dppz)2] (3) shows that the Gd(III) ion is coordinated to six oxygen atoms from three bidentate nitrate ligands and four nitrogen atoms from two bidentate TTF-dppz molecules forming a distorted bicapped square antiprism coordination geometry. The UV-vis spectra of the four Ln(III) complexes show very strong absorption bands in the UV region consistent with ligand centred electronic π-π* transitions and an intense broad absorption band in the visible region corresponding to a spin-allowed electronic π-π* 1ILCT transition from the TTF-dppz ligand. Upon coordination, the 1ILCT band of the free TTF-dppz ligand is bathochromically shifted. The electrochemical studies reveal that all complexes undergo two reversible oxidation and one (quasi)reversible reduction processes, ascribed to the successive oxidations of the TTF moiety and the reduction of the dppz unit, respectively. Moreover, the magnetic properties of complexes 3 and 4 are discussed. 相似文献
49.
The chemical composition of surgical smoke, a gaseous by-product of some surgical devices??lasers, drills, vessel sealing devices??is of great interest due to the many toxic components that have been found to date. For the first time, surgical smoke samples collected during routine keyhole surgery were analyzed with infrared laser spectroscopy. Traces (ppm range) of methane, ethane, ethylene, carbon monoxide and sevoflurane were detected in the samples which consisted mostly of carbon dioxide and water vapor. Except for the anaesthetic sevoflurane, none of the compounds were present at dangerous concentrations. Negative effects on the health of operation room personnel can be excluded for many toxic compounds found in earlier studies, since their concentrations are below recommended exposure limits. 相似文献
50.
Yuan HQ Agterberg DF Hayashi N Badica P Vandervelde D Togano K Sigrist M Salamon MB 《Physical review letters》2006,97(1):017006
We investigate the order parameter of noncentrosymmetric superconductors Li2Pd3B and Li2Pt3B via the behavior of the penetration depth lambda(T). The low-temperature penetration depth shows BCS-like behavior in Li2Pd3B, while in Li2Pt3B it follows a linear temperature dependence. We propose that broken inversion symmetry and the accompanying antisymmetric spin-orbit coupling, which admix spin-singlet and spin-triplet pairing, are responsible for this behavior. The triplet contribution is weak in Li2Pd3B, leading to a wholly open but anisotropic gap. The significantly larger spin-orbit coupling in Li2Pt3B allows the spin-triplet component to be larger in Li2Pt3B, producing line nodes in the energy gap as evidenced by the linear temperature dependence of lambda(T). The experimental data are in quantitative agreement with theory. 相似文献