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861.
The measurement uncertainty of illuminance and, consequently, luminous flux and luminous efficacy of LED lamps can be reduced with a recently introduced method based on the predictable quantum efficient detector (PQED). One of the most critical factors affecting the measurement uncertainty with the PQED method is the determination of the aperture area. This paper describes an upgrade to an optical method for direct determination of aperture area where superposition of equally spaced Gaussian laser beams is used to form a uniform irradiance distribution. In practice, this is accomplished by scanning the aperture in front of an intensity-stabilized laser beam. In the upgraded method, the aperture is attached to the PQED and the whole package is transversely scanned relative to the laser beam. This has the benefit of having identical geometry in the laser scanning of the aperture area and in the actual photometric measurement. Further, the aperture and detector assembly does not have to be dismantled for the aperture calibration. However, due to small acceptance angle of the PQED, differences between the diffraction effects of an overfilling plane wave and of a combination of Gaussian laser beams at the circular aperture need to be taken into account. A numerical calculation method for studying these effects is discussed in this paper. The calculation utilizes the Rayleigh–Sommerfeld diffraction integral, which is applied to the geometry of the PQED and the aperture. Calculation results for various aperture diameters and two different aperture-to-detector distances are presented. 相似文献
862.
In this paper we investigate the controlled dense coding with the maximal slice states. Three schemes are presented. Our schemes employ the maximal slice states as quantum channel, which consists of the tripartite entangled state from the first party(Alice), the second party(Bob), the third party(Cliff). The supervisor(Cliff) can supervises and controls the channel between Alice and Bob via measurement. Through carrying out local von Neumann measurement, controlled-NOT operation and positive operator-valued measure(POVM), and introducing an auxiliary particle, we can obtain the success probability of dense coding. It is shown that the success probability of information transmitted from Alice to Bob is usually less than one. The average amount of information for each scheme is calculated in detail. These results offer deeper insight into quantum dense coding via quantum channels of partially entangled states. 相似文献
863.
Molly Dunkum 《Czechoslovak Mathematical Journal》2009,59(1):241-247
There is a classical result known as Baer’s Lemma that states that an R-module E is injective if it is injective for R. This means that if a map from a submodule of R, that is, from a left ideal L of R to E can always be extended to R, then a map to E from a submodule A of any R-module B can be extended to B; in other words, E is injective. In this paper, we generalize this result to the category q
ω consisting of the representations of an infinite line quiver. This generalization of Baer’s Lemma is useful in proving that
torsion free covers exist for q
ω.
相似文献
864.
The blow-up in finite time for the solutions to the initial-boundary value problem associated to the multi-dimensional quantum
hydrodynamic model in a bounded domain is proved. The model consists on conservation of mass equation and a momentum balance
equation equivalent to a compressible Euler equations corrected by a dispersion term of the third order in the momentum balance.
The proof is based on a priori estimates for the energy functional for a new observable constructed with an auxiliary function,
and it is shown that, under suitable boundary conditions and assumptions on the initial data, the solution blows up after
a finite time.
I.M. Gamba is supported by NSF-DMS0507038. M.P. Gualdani acknowledges partial support from the Deutsche Forschungsgemeinschaft,
grants JU359/5 and was partially supported under the Feodor Lynen Research fellowship. P. Zhang is partially supported by
the NSF of China under Grant 10525101 and 10421101, and the innovation grant from the Chinese Academy of Sciences. Part of
the work was done when P. Zhang visited the Department of Mathematics of Texas University at Austin, the author would like
to thank the hospitality of the department. Support from the Institute for Computational Engineering and Sciences at the University
of Texas at Austin is also gratefully acknowledged. 相似文献
865.
Sylvain Col 《Periodica Mathematica Hungarica》2009,58(1):1-23
Les propriétés multiplicatives des nombres ellipséphiques peuvent être obtenues à l’aide des moments de la série génératrice
de cette suite. Nous donnons des estimations précises pour les grands moments par deux méthodes distinctes: l’une combinatoire
fournit un résultat précis dans le cas réputé le plus difficile des nombres n’utilisant que les 0 et les 1; la seconde purement
analytique fournit un résultat sans condition sur les chiffres.
相似文献
866.
In 1907 W. H. Young classified the real-valued Baire one functions on the line which have the Darboux (intermediate-value)
property as those which are bilaterally approachable. Here we investigate generalizations of this theorem to the setting of
real-valued Baire one functions of several variables which possess various “Darboux-like” properties.
相似文献
867.
Joaquín Sicilia Luis A. San-José Juan García-Laguna 《Annals of Operations Research》2009,169(1):93-115
We study an inventory system where demand on the stockout period is partially backlogged. The backlogged demand ratio is a
mixture of two exponential functions. The shortage cost has two significant costs: the unit backorder cost (which includes
a fixed cost and a cost proportional to the length of time for which the backorder exists) and the cost of lost sales. A general
procedure to determine the optimal policy and the minimum inventory cost for all the parameter values is developed. This model
generalizes several inventory systems analyzed by different authors. Numerical examples are used to illustrate the theoretical
results. 相似文献
868.
Balázs Csikós György Kiss Konrad J. Swanepoel P. Oloff de Wet 《Periodica Mathematica Hungarica》2009,58(2):129-138
A family {A
i
| i ∈ I} of sets in ℝ
d
is antipodal if for any distinct i, j ∈ I and any p ∈ A
i
, q ∈ A
j
, there is a linear functional ϕ:ℝ
d
→ ℝ such that ϕ(p) ≠ ϕ(q) and ϕ(p) ≤ ϕ(r) ≤ ϕ(q) for all r ∈ ∪
i∈I
A
i
. We study the existence of antipodal families of large finite or infinite sets in ℝ3.
The research was supported by the Hungarian-South African Intergovernmental Scientific and Technological Cooperation Programme,
NKTH Grant no. ZA-21/2006 and South African National Research Foundation Grant no. UID 61853, as well as Hungarian National
Foundation for Scientific Research Grants no. NK 67867, no. T47102, and no. K72537. 相似文献
869.
We prove that several types of open Riemann surfaces, including the finitely connected planar domains, embed properly into
such that the values on any given discrete sequence can be arbitrarily prescribed.
Kutzschebauch supported by Schweizerische Nationalfonds grant 200021-107477/1. 相似文献
870.
Jong Yoon Hyun 《Designs, Codes and Cryptography》2009,50(2):173-185
We present generalized MacWilliams identities for binary codes. These identities naturally lead to the concepts of the local
weight distribution of a binary code with respect to a word u and its MacWilliams u-transform. In the case that u is the all-one word, these ones correspond to the weight distribution of a binary code and its MacWilliams transform, respectively.
We identify a word v with its support, and consider v as a subset of {1, 2,..., n}. For two words u,w of length n such that their intersection is the empty set, define the u-face centered at w to be the set . A connection between our MacWilliams u-transform and the weight distribution of a binary code in the u-face centered at the zero word is presented. As their applications, we also investigate the properties of a perfect binary
code. For a perfect binary code C, the main results are as follows: first, it is proved that our local weight distribution of C is uniquely determined by the number of codewords of C in the orthogonal u-face centered at the zero word. Next, we give a direct proof for the known result, concerning the weight distribution of
a coset of C in the u-face centered at the zero word, by A. Y. Vasil’eva without using induction. Finally, it is proved that the weight distribution
of C in the orthogonal u-face centered at w is uniquely determined by the codewords of C in the u-face centered at the zero word.
相似文献