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141.
142.
James King Bidwell 《School science and mathematics》1966,66(7):661-669
143.
B. Pietrzyk R. Barate P. Bareyre P. Bonamy P. Borgeaud M. David F.X. Gentit G. Laurens Y. Lemoigne G. Villet S. Zaninotti P. Astbury A. Duane G.J. King B.C. Nandi R. Namjoshi D.M. Websdale J. Wiejak T. Marshall 《Physics letters. [Part B]》1982,113(1):105-112
A lepton-pair trigger was used to select a hadronic system in different flavour and colour states: properties of the transformation of this system into hadrons were measured in terms of charge flow, multiplicity distribution, and fragmentation function. It is observed that, while the effects of flavour are clearly seen, the colour degrees of freedom are not observed in the region of low pT. 相似文献
144.
H.H. Chang B.W. Ridley T.H. Braid T.W. Conlon E.F. Gibson N.S.P. King 《Nuclear Physics A》1978,297(1):105-124
The differential cross sections for the elastic scattering of 3He ions on targets of 40Ca and 58Ni have been measured at incident energies of 27.7, 51.4, 73.2 and 83.5 MeV. The results of optical model analyses showed that only one unique potential (JR ≈ 330 MeV · fm3) with a surface absorptive term can provide acceptable fits to the large angle elastic scattering cross sections at 83.5 MeV. The particular geometrical set found at 83.5 MeV could not, however, give an adequate fit to the data with energy less than 40 MeV. Subsequent analyses indicated that a break in the energy dependence of the real potential is observed for the low energy data. Explicit energy dependent terms were obtained by fitting all the data simultaneously. These phenomenological potentials were also compared with the folded nucleon-nucleus potential. The influence of the α-particle channels on the elastic scattering of 3He ions at 83.5 MeV was also examined. 相似文献
145.
A very low-pressure pyrolysis (VLPP) apparatus has been constructed and shown to yield kinetic data consistent with other VLPP systems. The technique has been applied to the pyrolysis of cyclobutyl cyanide over the temperature range of 833–1203°K. The reaction was found to proceed via a single pathway to yield ethylene and vinyl cyanide. If A∞ is based on previous high-pressure data for this reaction and for cyclobutane pyrolysis, then RRKM theory calculations show that the experimental unimolecular rate constants are consistent with the high-pressure Arrhenius parameters given by where θ=2.303 RT in kcal/mole. If A∞ is adjusted relative to the more recent parameters for cyclobutane pyrolysis suggested by VLPP studies, then the Arrhenius expression becomes The cyano group reduces the activation energy for cyclobutane pyrolysis by 6±1 kcal/mole, and on the basis of a biradical mechanism this value may be attributed to the cyano stabilization energy. 相似文献
146.
T. C.?King Y. K.?KuoEmail author 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,45(4):515-521
The small-size partially filled one-dimensional (1D) lattice gas system with
1/rδ repulsive interactions is numerically studied. Our results
indicate that phase change with vacancy ordering involved exists in the
partially filled 1D lattice gas systems, and the phase properties of the
studied system strongly depend on the occupancy nav and the interaction
strength δ. Most interestingly, it is found that the phase change
still exists in the 1D finite-size lattice gas systems even with nearest
neighbor interactions, i.e. δ is infinite. These results provide
valuable information about the phase properties of 1D confined systems, such
as molecules inside the carbon nanotubes, with long-range interactions
between particles. 相似文献
147.
The dissociation of ethane on Pt{110}-(1 x 2) has been studied using supersonic molecular beam and temperature-programmed reaction techniques. The study unequivocally shows that the stable dissociation product of ethane on Pt{110}-(1 x 2) at all coverages is CCH2 at 350-400 K and CCH at 440 K. Temperature-programmed-reaction (TPR) experiments indicate that the CCH2 species decomposes to CCH with a reaction-limited peak temperature of 430 K. Above 450 K, the CCH species becomes unstable and decomposes with a peak temperature of 540 K. By 600 K, ethane dehydrogenates completely to form a surface carbon layer. The sticking probability is initially 0.02 at 370 K and 0.03 at 600 K and follows a linear (1-2theta) dependence for coverages of up to theta = 0.4 ML, where theta is defined as the number of C2Hx units per (1 x 2) unit cell. However, a much weaker coverage dependence at 800 K suggests that the carbon agglomerates into high-density islands. 相似文献
148.
The low-energy electron diffraction (LEED) pattern of the step-kinked Pt{531} surface at 200 K shows energy-dependent cancellation of diffraction spots over unusually large energy ranges, up to 100 eV. This cannot be reproduced theoretically when a flat surface geometry is assumed. A relatively simple model of roughening, however, involving 0.25 ML of vacancies and adatoms leads to very good agreement with the experiment. The cancellation of intensities within a very narrow range of adatom or vacancy coverages is caused by the interference of electrons emerging from different heights but similar local environments. This is a rare example where the energy dependence of integrated LEED spot intensities is dramatically affected by the long-range arrangement of atoms. 相似文献
149.
We report a technique that is capable of making simultaneous two-point time-series measurements of minor-species concentrations in turbulent flames. The experimental setup, which incorporates picosecond time-resolved laser-induced fluorescence, has a spatial resolution of less than 250 microm and a temporal resolution of less than 100 micros, which spatially and temporally resolve microscales in many turbulent flows. Two-point time-series data are given for a standard turbulent nonpremixed flame at Re= 10,000, including a discussion of potential implications. 相似文献
150.
Ranea VA Michaelides A Ramírez R de Andres PL Vergés JA King DA 《Physical review letters》2004,92(13):136104
Based on the results of density functional theory calculations, a novel mechanism for the diffusion of water dimers on metal surfaces is proposed, which relies on the ability of H bonds to rearrange through quantum tunneling. The mechanism involves quasifree rotation of the dimer and exchange of H-bond donor and acceptor molecules. At appropriate temperatures, water dimers diffuse more rapidly than water monomers, thus providing a physical explanation for the experimentally measured high diffusivity of water dimers on Pd[111] [Science 297, 1850 (2002)]]. 相似文献