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71.
Sensitive gas chromatographic procedures for the determination of methoxyphenamine and three of its metabolites in plasma have been developed. The metabolites were measured using an electron-capture detector. This simple procedure is based on the precipitation of protein from a 1-ml plasma sample with 10% trichloroacetic acid, followed by aqueous derivatization with pentafluorobenzoyl chloride at pH 9.2 and a single-step cyclohexane extraction. The lower limit of detection for the N-desmethyl, O-desmethyl and aromatic 5-hydroxy metabolites of methoxyphenamine were 1.6, 3.1 and 2.2 ng ml-1, respectively, with coefficients of variation less than 10%. The poor electron-capture response of fluorinated derivatives of methoxyphenamine necessitated the use of nitrogen-phosphorus detection. Extractive derivatization with pentafluorobenzoyl chloride, without the need for protein precipitation, enabled quantitation of methoxyphenamine down to 3.8 ng ml-1 from a 2-ml aliquot of plasma. In a pilot study involving healthy volunteers who received a single oral dose of methoxyphenamine hydrochloride plasma concentration could be followed in all three subjects for at least 24, 32, 12 and 4 h for methoxyphenamine and the O-desmethyl, 5-hydroxy and N-desmethyl metabolites, respectively. 相似文献
72.
The sorption equilibrium and kinetics of cadmium ions from aqueous solution onto bone char have been studied. Equilibrium isotherms for the sorption system were correlated by Langmuir and bi-Langmuir equations. The application of the bi-Langmuir equation was developed because the mechanistic analysis in this research indicated that cadmium removal occurs ion exchange and physical adsorption onto different surface sites. The bi-Langmuir equation provides a better fit to the experimental data. In addition, the removal rates of cadmium ions based on the Langmuir models have been investigated. The effective diffusivity was calculated using the effects of initial metal ion concentration and bone char mass. Two mass-transport models based on film-pore diffusion control have been applied to analyze the concentration decay curves. The film and pore diffusion coefficients using an analytical equation are equal to 1.26x10(-3) cm/s and 5.06x10(-7) cm(2)/s, respectively. The pore diffusion coefficient obtained from the numerical method is 4.89x10(-7) cm(2)/s. A sensitivity analysis showed that the film-pore diffusion model and constant effective diffusivity could be used to describe the mass-transport mechanism of the sorption system with a high degree of correlation. Copyright 2001 Academic Press. 相似文献
73.
Csorna SE Garren L Mestayer MD Panvini RS Yi X Alam MS Avery P Bebek C Berkelman K Cassel DG Copie T DeSalvo R DeWire JW Ehrlich R Ferguson T Galik R Gilchriese MG Gittelman B Halling M Hartill DL Holzner S Ito M Kadaswamy J Kreinick DL Kubota Y Mistry NB Nordberg E Ogg M Peterson D Perticone D Read K Silverman A Stein PC Stone S Kezun X Sadoff AJ Giles RT Hassard J Hempstead M Kinoshita K McKay WW Pipkin FM Wilson R Haas P Jensen T Kagan H Kass R Behrends S Gentile T Guida JM Guida JA Morrow F 《Physical review letters》1985,54(17):1894-1897
74.
Vadim A. Medvedev Michael E. Efimov Paul J. Cerutti Robert M. McKay Lawrence H. Johnson Loren G. Hepler 《Thermochimica Acta》1978,23(1):87-92
We have made calorimetric measurements of the enthalpy of solution of NH4NO3(c, IV) in water at 298 K, where (c, IV) indicates the crystal form of amomonium nitrate that is stable from 256 to 305 K. Results of our measurements have been combined with enthalpy of dilution values from Parker to obtain the standard enthalpy of solution of NH4NO3 (c, IV) in water at 298.15 K to be ΔHo = 25.41 kJ mol?1. 相似文献
75.
We present the numbers of isotopy classes and main classes of Latin squares, and the numbers of isomorphism classes of quasigroups and loops, up to order 10. The best previous results were for Latin squares of order 8 (Kolesova, Lam, and Thiel, 28 ), quasigroups of order 6 (Bower, 7 ), and loops of order 7 (Brant and Mullen, 8 ). The loops of order 8 have been independently found by “QSCGZ” and Guérin (unpublished, 25 ). We also report on the most extensive search so far for a triple of mutually orthogonal Latin squares (MOLS) of order 10. Our computations show that any such triple must have only squares with trivial symmetry groups. © 2006 Wiley Periodicals, Inc. J Combin Designs 相似文献
76.
It is possible to compute and its modular equations with no perception of its related classical group structure except at . We start by taking, for prime, an unknown ``-Newtonian' polynomial equation with arbitrary coefficients (based only on Newton's polygon requirements at for and ). We then ask which choice of coefficients of leads to some consistent Laurent series solution , (where . It is conjectured that if the same Laurent series works for -Newtonian polynomials of two or more primes , then there is only a bounded number of choices for the Laurent series (to within an additive constant). These choices are essentially from the set of ``replicable functions,' which include more classical modular invariants, particularly . A demonstration for orders and is done by computation. More remarkably, if the same series works for the -Newtonian polygons of 15 special ``Fricke-Monster' values of , then is (essentially) determined uniquely. Computationally, this process stands alone, and, in a sense, modular invariants arise ``spontaneously.'
77.
78.
The equationbelongs to the class of linear functional equations. The solutions form a linear space with respect to the usual pointwise operations. According to the classical results of the theory they must be generalized polynomials. New investigations have been started a few years ago. They clarified that the existence of non-trivial solutions depends on the algebraic properties of some related families of parameters. The problem is to find the necessary and sufficient conditions for the existence of non-trivial solutions in terms of these kinds of properties. One of the earliest results is due to Z. Daróczy [1]. It can be considered as the solution of the problem in case of n = 2. We are going to take more steps forward by solving the problem in case of n = 3.
相似文献
$$\sum^{n}_ {i=0} a_{i}f(b_{i}x + (1 - b_{i})y) = 0$$
79.
Let M be a connected complex projective manifold such that c1(T(1,0)M)=0. If M admits a holomorphic Cartan geometry, then we show that M is holomorphically covered by an abelian variety. 相似文献
80.
Conditions are found under which the expected number of automorphisms of a large random labelled graph with a given degree
sequence is close to 1. These conditions involve the probability that such a graph has a given subgraph. One implication is
that the probability that a random unlabelledk-regular simple graph onn vertices has only the trivial group of automorphisms is asymptotic to 1 asn → ∞ with 3≦k=O(n
1/2−c). In combination with previously known results, this produces an asymptotic formula for the number of unlabelledk-regular simple graphs onn vertices, as well as various asymptotic results on the probable connectivity and girth of such graphs. Corresponding results
for graphs with more arbitrary degree sequences are obtained. The main results apply equally well to graphs in which multiple
edges and loops are permitted, and also to bicoloured graphs.
Research of the second author supported by U. S. National Science Foundation Grant MCS-8101555, and by the Australian Department
of Science and Technology under the Queen Elizabeth II Fellowships Scheme. Current address: Mathematics Department, University
of Auckland, Auckland, New Zealand. 相似文献