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91.
O. Puglisi S. Pignataro P. Baeri E. Rimini S. Branca A. Romano 《Fresenius' Journal of Analytical Chemistry》1980,302(4):290-295
Summary Proton induced X-ray emission (PIXE) Spectra have been obtained for the blood serum of several old-age subjects by using the Van de Graaff accelerator of Catania University. The concentration levels of Cl, K, Ca, Br, Fe, Cu, Zn have been determined simultaneously within 2 min by using 5 l of blood serum. Good agreement with literature data has been found.
Simultanbestimmung von sieben Elementen (Cl, K, Ca, Br, Fe, Cu, Zn) im Blutserum mit Hilfe von PIXE
Zusammenfassung Mit Hilfe des Van de Graaff-Beschleunigers der Univ. Catania wurden PIXE-Spektren vom Blutserum mehrerer alter Personen aufgenommen. Mit einer Probe von 5 l konnten die obigen sieben Elemente innerhalb von 2 min bestimmt werden. Die Übereinstimmung mit Literaturangaben war gut.相似文献
92.
Romano P. Di Leo R. Nigro A. Cucolo A. M. Dabrowski B. Radaelli P. G. 《Il Nuovo Cimento D》1994,16(10):1885-1888
Il Nuovo Cimento D - We have realized planar tunnel junctions using both Y123 and Y124 single crystals as base electrodes and Pb as counterelectrode. The crystals, with T c=90 K (Y123) and T c=80 K... 相似文献
93.
Geometrodynamics vs. connection dynamics 总被引:5,自引:0,他引:5
Joseph D. Romano 《General Relativity and Gravitation》1993,25(8):759-854
The purpose of this review is to describe in some detail the mathematical relationship between geometrodynamics and connection dynamics in the context of the classical theories of 2+1 and 3+1 gravity. We analyze the standard Einstein-Hilbert theory (in any spacetime dimension), the Palatini and Chern-Simons theories in 2+1 dimensions, and the Palatini and self-dual theories in 3+1 dimensions. We also couple varions matter fields to these theories and briefly describe a pure spin-connection formulation of 3+1 gravity. We derive the Euler-Lagrange equations of motion from an action principle and perform a Legendre transform to obtain a Hamiltonian formulation of each theory. Since constraints are present in all these theories, we construct constraint functions and analyze their Poisson bracket algebra. We demonstrate, whenever possible, equivalences between the theories. 相似文献
94.
Künsch (1989, Ann. Statist.17 1217-1241) and Liu ane Singh (1992, in Exploring Limits of Bootstrap (R. Le Page and L. Billard, Eds.), pp. 225-248, Wiley, New York) have recently introduced a block resampling method that is successful in deriving consistent bootstrap estimates of distribution and variance for the sample mean of a strong mixing sequence. Raïs and Moore (1990, in Interface ′90) and Raïs (1992, Ph.D. Thesis, University of Montreal) extended the results of Künsch and Liu and Singh in the case of the sample mean of a homogeneous strong mixing random field in two dimensions (n = 2). In this paper, the general case (n Z+) is considered, and a resampling technique for strong mixing random fields is formulated, which is an extension of the "blocks of blocks" resampling scheme for sequences in Politis and Romano (1992, Ann. Statist.20 (4) 1985-2007). The "blocks of blocks" method can be used to construct asymptotically correct confidence intervals for parameters of the whole (infinite-dimensional) joint distribution of the random field, for example, the spectral density at a point. A variation of the "blocks of blocks" resampling scheme that involves "wrapping" the data around on a torus will also be studied, in view of its property to yield an unbiased bootstrap distribution. 相似文献
95.
Giorgio Barbieri Rois Benassi Romano Grandi Ugo Maria Pagnoni Ferdinando Taddei 《Magnetic resonance in chemistry : MRC》1979,12(3):159-162
The relative reactivity toward protonation and methylation of the two nitrogen atoms in N,N-dimethylaminopyridines has been examined by 1H NMR. The ring position of the dimethylamino group has no influence on protonation, which occurs in all the derivatives at the heterocyclic nitrogen. The N-methylation reaction does not follow a homogeneous behaviour, occurring at the exocyclic nitrogen in the 2-substituted dimethylamino derivative. The electronic characteristics of the molecules, determined by MO calculations at a semi-empirical level, indicate that both protonation and methylation should occur at the heterocyclic nitrogen; the calculated relative stabilites, however, of the N-protonated and N-methylated forms are in full agreement with the experimental results, and it appears that the anomalous behaviour of 2-dimethylaminopyridine in the N-methylation reaction is caused by steric factors. 相似文献
96.
G Musumarra G Scarlata G Cirma G Romano S Palazzo S Clementi G Giulietti 《Journal of chromatography. A》1985,350(1):151-168
Principal component analysis of standardized RF values in four eluent systems [ethyl acetate-methanol-30% ammonia (85:10:15), cyclohexane-toluene-diethylamine (65:25:10), ethyl acetate-chloroform (50:50) and acetone, with the plate dipped in potassium hydroxide solution] provided a two-component model which accounts for 73% of the total variance. The "scores" plot allowed the restriction of the range of inquiry to a few candidates. This result is of great practical significance in analytical toxicology, especially when account is taken of the cost, the time, the analytical instrumentation and the simplicity of the calculations required by the method. 相似文献
97.
This paper deals with the application of Hybrid Automatic Repeat reQuest (h-arq) techniques to allow reliable data communications in wireless 3G networks. Basically, retransmission of coded data is endowed with soft combining schemes applied, respectively, to packet replicas, or to decoding algorithm outputs. In particular, the proposed coding scheme takes advantage of error correction capabilities of the turbo codes, while the combining algorithm follows the diversity approach. The performance of the proposedh-arq schemes has been derived by means of a suitable analytical approach and numerical simulations in the case of a typical umts environment. The results highlight the good behavior of the proposed scheme in term of error rate, throughput, packet delivery delay and power reduction. 相似文献
98.
99.
Stress-induced crystallization of a crosslinked polybutadiene with a high 1,4-cis content is investigated, at room temperature. The change in the fraction of crystallinity with deformation is evaluated by two different methods. The first is based on simultaneous measurement of birefringence and stress. The second is based on calorimetric analysis. The data on crystallinity obtained by these two methods are in good agreement in the range of low deformations, while, in the range of higher deformation (λ > 5), the degree of crystallinity obtained by calorimetry is higher than that obtained by the optical method. Qualitative information on the crystallization was also obtained by optical analysis of the hysteresis behavior. The hysteresis data show the presence of ordering phenomena at deformations at which there seems to be no crystallinity according to both quantitative methods. 相似文献
100.