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排序方式: 共有163条查询结果,搜索用时 245 毫秒
1.
Noli Fotini Papadopoulos Pavlos Kolias Pavlos Tsiridis Eleftherios Papavasiliou Kyriakos Sayegh Fares 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(2):621-628
Determination of metals and trace elements in patients with total knee or hip arthroplasty with CoCrMo alloy was performed. Blood, urine and cerebrospinal fluid (CSF) samples were analyzed and compared with samples from healthy people. Levels of Co, Cr as well as Na, Ca, Fe, Zn, Se, Rb, Sb and Br were determined by means of neutron activation analysis. The values of Cr and Co of the blood and urine measurements were elevated in patients with replacement, and according to the statistical analysis, significant differences of the elements Zn, Br, Co and Sb were found in the CSF (p?<?0.05).
相似文献2.
Shoenfield's unramified version of Cohen's forcing is defined in two stages: one which does not preserve double negation and the other which modifies the former so as to preserve double negation. Here we express the unramified forcing, which preserves double negation, in a single stage. Surprisingly enough, the corresponding definition of forcing for equality acquires a rather simple form. In [2] forcing ∥- is expressed in terms of strong forcing \( \Vdash * \) viap∥-Q iffp \( \Vdash * \) ¬ ¬Q for every formulaQ ofZF set theory and every elementp of a partially ordered set (P, ≦). In its turn,p \( \Vdash * \) Q is defined by the following five clauses: (1) $$p \Vdash * a \in biff(\exists c)(\exists q \geqq p)((c,q) \in b \wedge p \Vdash * a = c)$$ (2) $$\begin{gathered} p \Vdash * a \ne biff(\exists c)(\exists q \geqq p)(((c,q) \in a \wedge p \Vdash * c \notin b) \hfill \\ ((c,q) \in b \wedge p \Vdash * c \notin a)) \hfill \\ \end{gathered} $$ (3) $$p \Vdash * \neg Qiff(\forall q)(q \leqq p \to \neg (q \Vdash * Q))$$ (4) $$p \Vdash * (Q \vee S)iff(p \Vdash * Q) \vee (p \Vdash * S)$$ (5) $$p \Vdash * (\exists x)Q(x)iff(\exists b)(p \Vdash * Q(b))$$ . 相似文献
3.
Ataloglou T Bourikas K Vakros J Kordulis C Lycourghiotis A 《The journal of physical chemistry. B》2005,109(10):4599-4607
In the present work we studied, for the first time, the kinetics of adsorption of the Co(H(2)O)(6)(2+) species on the "electrolytic solution/gamma-Al(2)O(3)" interface at pH = 7 and 25 degrees C for a very broad range of Co(II) surface concentrations ranged from 0.03 to 6 theoretical Co(H(2)O)(6)(2+) surface layers. Moreover, we studied the surface dissolution of gamma-alumina in the presence of the Co(H(2)O)(6)(2+) ions in the impregnating solution, the contribution of the Co(II) desorption on the whole deposition process and the deposition isotherm. It was found that under the conditions where the deposition has taken place, the dissolution of the gamma-alumina surface is negligible even in the presence of the Co(H(2)O)(6)(2+) species in the impregnating solution. It was, moreover, inferred that the Co(II) desorption does not participate significantly to the whole deposition process. It was found that the deposition kinetics may be described by the following kinetic expression r(Co,bulk) = k'C(Co,bulk)(2), which relates the rate of disappearance of the Co(H(2)O)(6)(2+) ions from the impregnating solution, r(Co,bulk,) with their concentration C(Co,bulk). This kinetic expression may be derived assuming the following deposition scheme: nS + 2[Co(H(2)O)(6)(2+)] --> S(n) - [Co(H(2)O)(x,x)(<)(6)(2+)](2), where S represents the surface reception sites. The above expressions indicated that two Co(H(2)O)(6)(2+) ions are involved, from the side of the interface, in the reaction with the reception sites. It seems probable that the deposition step involves the simultaneous adsorption and dimerization of the two interfacial Co(H(2)O)(6)(2+) ions through (hydr)oxobridges. On the other hand, the sigmoidal form of the deposition isotherm and the dependence of the apparent rate constant, k', on the interfacial Co(II) concentration suggested that the already deposited Co(II) species may be involved in the reception sites, S, promoting the adsorption and resulting to the formation of multinuclear complexes and Co(II) surface precipitates. Finally, reasonable interface potential values for oxides were determined for the first time using kinetic results. 相似文献
4.
Timothy J. Hingston Kyriakos Porfyrakis G. Andrew D. Briggs 《Tetrahedron letters》2006,47(42):7413-7415
The synthesis of a short-chain fullerene dimer via bifunctional cycloaddition is demonstrated. A mono-functionalised C60 species is isolated, and has the potential for further organic functionalisation. 相似文献
5.
Kanai M Porfyrakis K Briggs GA Dennis TJ 《Chemical communications (Cambridge, England)》2004,(2):210-211
We report the purification of the nitrogen-containing incar-fullerenes iNC(60) and iNC(70), and their characterisation by UV-Vis absorption spectroscopy. 相似文献
6.
Miaoyong Cao John Wesson Kyriakos Loufakis Bernhard Wunderlich Martin Möller 《Molecular Crystals and Liquid Crystals》2013,570(2-4):231-241
Three cyclic methyl and ethyl substituted silanes were synthesized and their thermal properties analyzed. All show a plastic crystalline state which permits also ring and/or side-chain conformational motion as judged from the enthalpies of transition to the isotropic state. Heat capacity data and entropies of disordering into the plastic crystal leave open the possibility of a condis (conformationally disordered) state below the plastic crystal state with a continuous, transitionless freezing of the conformational motion at lower temperature. 相似文献
7.
Anastasios K. Papageorgiou Evangelos M. Papoutsis-Kiachagias Kyriakos C. Giannakoglou 《国际流体数值方法杂志》2022,94(1):59-75
This article contributes to the development of methods for shape optimization under uncertainties, associated with the flow conditions, based on intrusive Polynomial Chaos Expansion (iPCE) and continuous adjoint. The iPCE to the Navier–Stokes equations for laminar flows of incompressible fluids is developed to compute statistical moments of the Quantity of Interest which are, then, compared with those obtained through the Monte Carlo method. The optimization is carried out using a continuous adjoint-enabled, gradient-based loop. Two different formulations for the continuous adjoint to the iPCE PDEs are derived, programmed, and verified. Intrusive PCE methods for the computation of the statistical moments require mathematical development, derivation of a new system of governing equations and their numerical solution. The development is presented for a chaos order of two and two uncertain variables and can be used as a guide to those willing to extend this development to a different set of uncertain variables or chaos order. The developed method and software, programmed in OpenFOAM, is applied to two optimization problems pertaining to the flow around isolated airfoils with uncertain farfield conditions. 相似文献
8.
James S. Pizey Kyriakos Symeonides 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2)
Abstract We have found that the treatment of certain β-keto-esters or 1,3-diketones with thionyl chloride gives either a sulphide or a sulphinyl chloride together with the chloro-compound depending on the structure of the active methylene compound. In certain cases cyclisation of sulphide provides a useful route to a 1,4-oxathiin. 相似文献
9.
Kyriakos C. Stylianou John Bacsa Darren Bradshaw Matthew J. Rosseinsky 《无机化学与普通化学杂志》2014,640(11):2123-2131
The reaction of NiII with a tetra‐benzoate pyrene ligand produces a 3D porous framework based on infinite 1D NiII chains. The NiII–O connectivity and the formation of a hydroxo‐bridge (μ3‐OH) responsible for the connection of the central NiII atoms within the 1D NiII–(μ3‐OH)2–NiII chains can be straightforwardly compared with the TiIV–O–TiIV connectivity seen in TiO2. The arrangement of the TBAPy ligand around the 1D rutile‐based chains leads in the generation of a porous framework with two distinct types of pores; based on the chemistries of these two types of pores, one can be labelled as hydrophobic and the other as hydrophilic. The use of different activation methods results in the generation of either a porous framework free of guest molecules or a completely solvent‐free material, in which the terminal H2O molecules bound to NiII were removed, leading thus to a framework with open NiII sites. CO2 isotherms collected on both frameworks at 195 K and one barshowed type I isotherms characteristic of microporous materials (BET surface areas for: guest‐free framework: 257(3) m2 · g–1; solvent‐free framework: 362(2) m2 · g–1). The affinity of both networks at zero coverage for both CO2 and CH4 was found to be greater when the unsaturated NiII sites are available within the void space. 相似文献
10.
Morton JJ Tyryshkin AM Ardavan A Porfyrakis K Lyon SA Briggs GA 《Physical review letters》2005,95(20):200501
Systematic errors in spin rotation operations using simple rf pulses place severe limitations on the usefulness of the pulsed magnetic resonance methods in quantum computing applications. In particular, the fidelity of quantum logic operations performed on electron spin qubits falls well below the threshold for the application of quantum algorithms. Using three independent techniques, we demonstrate the use of composite pulses to improve this fidelity by several orders of magnitude. The observed high-fidelity operations are limited by pulse phase errors, but nevertheless fall within the limits required for the application of quantum error correction. 相似文献