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211.
Florian Luca. 《Mathematics of Computation》2001,70(234):893-896
For any , let be the th prime number. In this paper, we confirm a conjecture of Erdos and Stewart concerning all the solutions of the diophantine equation , when .
212.
Another Note on the Greatest Prime Factors of Fermat Numbers 总被引:1,自引:0,他引:1
For every positive integer k > 1, let P(k) be the largest prime divisor of k. In this note, we show that if Fm = 22m + 1 is the mth Fermat number, then P(Fm) 2m+2(4m + 9) + 1 for all m 4. We also give a lower bound of a similar type for P(Fa,m), where Fa,m = a2m + 1 whenever a is even and m a18.AMS Subject Classification (1991) 11A51 11J86 相似文献
213.
Federica Galluzzi 《Indagationes Mathematicae》2000,11(4):547
Let X be a complex abelian fourfold of Mumford-type and let V = H1(X,
). The complex Mumford-Tate group of X is isogenous to SL(2)3. We recover information about the Hodge structure of X using representations of the Lie algebras
(2)3 and
(8) acting on V
. Using these techniques we show that there is a Kuga-Satake variety A associated to X in such a way that A is isogenous to X32. 相似文献
214.
Solar System tests give nowadays constraints on the estimated value of the cosmological constant, which can be accurately
derived from different experiments regarding gravitational redshift, light deflection, gravitational time-delay and geodesic
precession. Assuming that each reasonable theory of gravitation should satisfy Solar System tests, we use these limits on
the estimated value of the cosmological constant to constrain extended theories of Gravity, which are nowadays studied as
possible theories for cosmological models and provide viable solutions to the cosmological constant problem and the explanation
of the present acceleration of the Universe. We obtain that the estimated values, from Solar System tests, for the parameters
appearing in the extended theories of Gravity are orders of magnitude bigger than the values obtained in the framework of
cosmologically relevant theories. 相似文献
215.
We investigate the dynamic advertising policies of two competing firms in a duopolistic industry, assuming a predatory phenomenon between their advertising campaigns. The resulting model is a differential game which is not linear-quadratic. We show that there exists a Markovian Nash equilibrium, and that it leads to time constant advertising strategies. According to this model, predatory advertising produces a negative externality: the interference between the advertising campaigns decreases the total demand of the market. 相似文献
216.
This paper is a preliminary work to address the problem of dynamical systems with parameters varying in time. An idea to predict their behavior is proposed. These systems are called transient systems, and are distinguished from steady systems in which parameters are constant. In particular, in steady systems the excitation is either constant (e.g., nought) or periodic with amplitude, frequency, and phase angle which do not vary in time. We apply our method to systems, which are subjected to a transient excitation that is neither constant nor periodic. The effect of switching-off and full-transient forces is investigated. The former can be representative of switching-off procedures in machines; the latter can represent earthquake vibrations, wind gusts, etc., acting on a mechanical system. This class of transient systems can be seen as the evolution of an ordinary steady system into another ordinary steady system, for both of which the classical theory of dynamical systems holds. The evolution from a steady system to the other is driven by a transient force, which is regarded as a map between the two steady systems. 相似文献
217.
The authors are glad for the opportunity to contribute to a volume in honour of professor Hartshorne, whose works always stands as a basic reference for researchers in Algebraic Geometry. 相似文献
218.
219.
220.
There is a wide range of potential applications of inorganic compounds, and metal coordination complexes in particular, in medicine but progress is hampered by a lack of methods to study their speciation. The biological activity of metal complexes is determined by the metal itself, its oxidation state, the types and number of coordinated ligands and their strength of binding, the geometry of the complex, redox potential and ligand exchange rates. For organic drugs a variety of readily observed spin I = 1/2 nuclei can be used (1H, 13C, 15N, 19F, 31P), but only a few metals fall into this category. Most are quadrupolar nuclei giving rise to broad lines with low detection sensitivity (for biological systems). However we show that, in some cases, heteronuclear NMR studies can provide new insights into the biological and medicinal chemistry of a range of elements and these data will stimulate further advances in this area. 相似文献