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131.
We systematically investigate the motion of slowly moving
matter--wave gap solitons in a nonlinear potential, produced by the
weak random spatial variation of the atomic scattering length. With
the weak randomness, we construct an effective-particle theory to
study the motion of gap solitons. Based on the effective-particle
theory, the effect of the randomness on gap solitons is obtained, and
the motion of gap solitons is finally solved. Moreover, the analytic
results for the general behaviours of gap soliton motion, such as the
ensemble-average speed and the reflection probability depending on
the weak randomness are obtained. We find that with the increase of
the random strength the ensemble-average speed of gap solitons
decreases slowly where the reduction is proportional to the variance
of the weak randomness, and the reflection probability becomes
larger. The theoretical results are in good agreement with the
numerical simulations based on the Gross--Pitaevskii equation. 相似文献
132.
In this paper, a new type of resonant Brewster filters (RBF) with surface relief structure for the multiple channels is first presented by using the rigorous coupled-wave analysis and the S-matrix method. By tuning the depth of homogeneous layer which is under the surface relief structure, the multiple channels phenomenon is obtained. Long range, extremely low sidebands and multiple channels are found when the RBF with surface relief structure is illuminated with Transverse Magnetic incident polarization light near the Brewster angle calculated with the effective media theory of sub wavelength grating. Moreover, the wavelengths of RBF with surface relief structure can be easily shifted by changing the depth of homogeneous layer while its optical properties such as low sideband reflection and narrow band are not spoiled when the depth is changed. Furthermore, the variation of the grating thickness does not effectively change the resonant wavelength of RBF, but have a remarkable effect on its line width, which is very useful for designing such filters with different line widths at desired wavelength. 相似文献
133.
We experimentally demonstrate amplitude squeezed soliton utilizing intensity-dependent self-phase modulation in an asymmetric Sagnac interferometer.The system.whose components are connected via ferrule connector/physical connection(FC/PC)fiber connectors,constitutes all-fiber configuration to generate squeezed soliton.Soliton amplitude reduction measured by homodyne detection is near 4.0 dB below the shot-noise level.Optimal squeezing fields in both simple and compact all-fiber configuration are obtained. 相似文献
134.
Machiel Van Frankenhuysen 《Journal of Number Theory》2002,95(2):289-302
Following Elkies (Internat. Math. Res. Notices7 (1991) 99-109) and Bombieri (Roth's theorem and the abc-conjecture, preprint, ETH Zürich, 1994), we show that the ABC conjecture implies the one-dimensional case of Vojta's height inequality. The main geometric tool is the construction of a Belyǐ function. We take care to make explicit the effectivity of the result: we show that an effective version of the ABC conjecture would imply an effective version of Roth's theorem, as well as giving an (in principle) explicit bound on the height of rational points on an algebraic curve of genus at least two. 相似文献
135.
Y. Yan 《International Journal of Infrared and Millimeter Waves》2002,23(7):1109-1117
The theory is presented for one method of determining the effective polarization parameters of the rain medium in the problem of polarization information processing of detecting target. The determination of the effective polarization parameters of the propagation medium is from the data of propagation measurements over a line-of-sight link. The polarization parameters the effective average value, the effective standard deviation and F the effective shape parameter of the propagation medium are obtained by means of the method of inverse scattering, showing a good agreement with the data from direct measurements. 相似文献
136.
Brian Hudson David J. Livingstone Elizabeth Rahr 《Journal of computer-aided molecular design》1989,3(1):55-65
Summary Pattern recognition methods, particularly the unsupervised learning techniques, are well suited for the preliminary analysis of the large data sets produced by computer chemistry. The use of linear and non-linear display methods for such exploratory analysis are exemplified with the aid of two data sets of biologically active molecules. Advantages and disadvantages of these techniques are discussed. 相似文献
137.
M.?B.?BarbaroEmail author R.?Cenni A.?Molinari M.?R.?Quaglia 《The European Physical Journal A - Hadrons and Nuclei》2004,22(3):377-390
We address the problem of two pairs of fermions living on an arbitrary number of single-particle levels of a potential well (mean field) and interacting through a pairing force in the framework of the Richardson equations. The associated solutions are classified in terms of a number vl, which reduces to the seniority v in the limit of a large pairing strength G and yields the number of pairs not developing a collective behaviour, their energy remaining finite in the G limit. We express analytically, through the moments of the single-particle levels distribution, the collective mode energy and the two critical values Gcr+ and Gcr- of the coupling which can exist on a single-particle level with no pair degeneracy. Notably Gcr+ and Gcr-, when the number of single particle levels goes to infinity, merge into the critical coupling of a one-pair system Gcr (when it exists), which is not envisioned by the Richardson theory. In correspondence of Gcr, the system undergoes a transition from a mean-field- to a pairing-dominated regime. We finally explore the behaviour of the excitation energies, wave functions and pair transfer amplitudes versus G finding out that the former, for G > Gcr-, come close to the BCS predictions, whereas the latter display a divergence at Gcr, signaling the onset of a long-range off-diagonal order in the system. 相似文献
138.
Let
be a unital C*-algebra and G the group of units of
. A geometrical study of the action of G over the set
+ of all positive elements of
is presented. The orbits of elements with closed range by this action are provided with a structure of differentiable homogeneous space with a natural connection. The orbits are partitioned in 'components' which also have a rich geometrical structure. 相似文献
139.
R. Dzh. Kasumova 《Journal of Applied Spectroscopy》2001,68(5):753-757
The theory of intracavity parametric interaction of the components of Raman scattering is developed in the prescribedintensity approximation, which takes into account the reverse reaction of the excited waves to the pumpingwave phase. It is shown that one can substantially improve the conversion efficiency or the amplification coefficient of the antiStokes component by selection of the intracavity geometry, the optimum phase relation between the interacting waves, the pumping level, and the phase mismatch. 相似文献
140.
Stanisaw Gnot Ewaryst Rafajowicz Agnieszka Urbaska-Motyka 《Annals of the Institute of Statistical Mathematics》2001,53(2):370-379
In the paper we consider a random linear model for observations provided by spatially located sensors measuring signals coming from one source. For this model a set of sufficient and complete statistics are found, and it is shown that the maximum likelihood estimators of unknown parameters (characteristics of the source) are functions of those statistics. The problem of nonnegative estimators of variance components of the model is shortly discussed. Comparisons of the mean squared errors of several estimators are given. Numerical example concerning hunting for defects in solar cells is considered in details. 相似文献