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941.
We present a discussion of the precision for the PHOTOS Monte Carlo algorithm, with improved implementation of QED interference
and multiple-photon radiation. The main application of PHOTOS is the generation of QED radiative corrections in decays of
any resonances, simulated by a "host" Monte Carlo generator. By careful comparisons automated with the help of the MC-TESTER
tool specially tailored for that purpose, we found that the precision of the current version of PHOTOS is of 0.1% in the case
of Z and W decays. In the general case, the precision of PHOTOS was also improved, but this will not be quantified here.
Received: 7 June 2005, Revised: 5 August 2005, Published online: 21 October 2005
Z. Was: Supported in part by the EU grant MTKD-CT-2004-510126, in partnership with the CERN Physics department, and Polish
State Committee for Scientific Research (KBN) grant 2 P03B 091 27 for the years 2004-2006 相似文献
942.
The nanocrystal samples of titanium dioxide doped with europium ion (Eu3+/TiO2 nanocrystal) are synthesized by the sol-gel method with hydrothermal treatment. The Eu3+ contents (molar ratio) in the samples are 0, 0.5%, 1%, 2%, 3% and 4%. The X-ray diffraction, UV-Vis spectroscopy data and scanning electron microscope image show that crystallite size is reduced by the doping of Eu3+ into TiO2. Comparing the Raman spectra of TiO2 with Eu3+/TiO2 (molar ratio Eu3+/TiO2=1%, 2% and 4%) nanocrystals at different annealing temperatures indicates that the anatase-to-rutile phase transformation temperatures of Eu3+/TiO2 nanocrystals are higher than that of TiO2. This is due to the formation of Eu-O-Ti bonds on the surface of the TiO2 crystallite, as characterized by the X-ray photoelectron spectroscopy. The photoluminescence spectra of TiO2 in Eu3+/TiO2 nanocrystals are interpreted by the surface self-trapped and defect-trapped exciton relaxation. The photoluminescence of Eu3+ in Eu3+/TiO2 nanocrystals has the strongest emission intensity at 2% of Eu3+ concentration. 相似文献
943.
E. F. Jones P. M. Gore S. J. Zhu J. H. Hamilton A. V. Ramayya J. K. Hwang R. Q. Xu L. M. Yang K. Li Z. Jiang Z. Zhang S. D. Xiao X. Q. Zhang W. C. Ma J. D. Cole M. W. Drigert I. Y. Lee J. O. Rasmussen Y. X. Luo M. A. Stoyer 《Physics of Atomic Nuclei》2006,69(7):1198-1203
We have used our analysis of γ-γ-γ data (5.7 × 1011 triples and higher folds) taken with Gammasphere from prompt γ rays emitted in the spontaneous fission of 252Cf to study the collective bands in 104,106,108Mo. The one-phonon and two-phonon γ-vibrational bands and known two-quasiparticle bands in neutron-rich 104,106Mo were extended to higher spins. The one-and two-phonon γ-vibrational bands have remarkably close energies for transitions from the same spin states and identical moments of inertia.
Several new bands are observed and are proposed as quasiparticle bands in 104,106Mo, along with the first β-type vibrational band in 106Mo. The quasiparticle bands have essentially constant moments of inertia near the rigid-body value that indicate blocking
of the pairing interaction. Candidates for chiral doublet bands in 106Mo are strong. These are the first reported chiral vibrational bands in an even-even nucleus.
The text was submitted by the authors in English. 相似文献
944.
S. Ota S. Shimoura H. Iwasaki M. Kurokawa S. Michimasa N. Aoi H. Baba K. Demichi Z. Elekes T. Fukuchi T. Gomi S. Kanno S. Kubono K. Kurita H. Hasegawa E. Ideguchi N. Iwasa Y.U. Matsuyama K.L. Yurkewicz T. Minemura T. Motobayashi T. Murakami M. Notani A. Odahara A. Saito H. Sakurai E. Takeshita S. Takeuchi M. Tamaki T. Teranishi Y. Yanagisawa K. Yamada M. Ishihara 《Physics letters. [Part B]》2008
945.
A fully implicit, spectral algorithm for the analysis of moving boundary problem is described. The algorithm is based on the concept of immersed boundary conditions (IBC), i.e., the computational domain is fixed while the time dependent physical domain is submerged inside the computational domain, and is described in the context of the diffusion-type problems. The physical conditions along the edges of the physical domain are treated as internal constraints. The method eliminates the need for adaptive grid generation that follows evolution of the physical domain and provides sharp resolution of the location of the boundary. Various tests confirm the spectral accuracy in space and the first- and second-order accuracy in time. The computational cost advantage of the IBC method as compared with the more traditional algorithm based on the mapping concept is demonstrated. 相似文献
946.
In this work, we have studied thermal stability of nanoscale Ag metallization and its contact with CoSi2 in heat-treated Ag(50 nm)/W(10 nm)/Co(10 nm)/Si(1 0 0) multilayer fabricated by sputtering method. To evaluate thermal stability of the systems, heat-treatment was performed from 300 to 900 °C in an N2 ambient for 30 min. All the samples were analyzed by four-point-probe sheet resistance measurement (Rs), Rutherford backscattering spectrometry (RBS), X-ray diffractometry (XRD), and atomic force microscopy (AFM). Based on our data analysis, no interdiffiusion, phase formation, and Rs variation was observed up to 500 °C in which the Ag layer showed a (1 1 1) preferred crystallographic orientation with a smooth surface and Rs of about 1 Ω/□. At 600 °C, a sharp increase of Rs value was occurred due to initiation of surface agglomeration, WSi2 formation, and interdiffusion between the layers. Using XRD spectra, CoSi2 formed at the Co/Si interface preventing W silicide formation at 750 and 800 °C. Meantime, RBS analysis showed that in this temperature range, the W acts as a cap layer, so that we have obtained a W encapsulated Ag/CoSi2 contact with a smooth surface. At 900 °C, the CoSi2 layer decomposed and the layers totally mixed. Therefore, we have shown that in Ag/W/Co/Si(1 0 0) multilayer, the Ag nano-layer is thermally stable up to 500 °C, and formation of W-capped Ag/CoSi2 contact with Rs of 2 Ω/□ has been occurred at 750-800 °C. 相似文献
947.
Bliokh KY Bliokh YP Freilikher V Genack AZ Hu B Sebbah P 《Physical review letters》2006,97(24):243904
We consider, both theoretically and experimentally, the excitation and detection of the localized quasimodes (resonances) in an open dissipative 1D random system. We show that, even though the amplitude of transmission drops dramatically so that it cannot be observed in the presence of small losses, resonances are still clearly exhibited in reflection. Surprisingly, small losses essentially improve conditions for the detection of resonances in reflection as compared with the lossless case. An algorithm is proposed and tested to retrieve sample parameters and resonance characteristics inside the random system exclusively from reflection measurements. 相似文献
948.
Sostaric JZ 《Ultrasonics sonochemistry》2008,15(6):1043-1048
Sonolysis of aqueous solutions of n-alkyl anionic surfactants results in the formation of secondary carbon-centered radicals (-*CH-). The yield of -*CH- depends on the bulk surfactant concentration up to a maximum attainable radical yield (the 'plateau yield') where an increasing surfactant concentration (below the critical micelle concentration) no longer affects the -*CH- yield. In an earlier study it was found that the ratio of -*CH- detected following sonolysis of aqueous solutions of sodium pentane sulfonate (SPSo) to that of sodium dodecyl sulfate (SDS) (i.e. CH(SPSo)/CH(SDS)) depended on the frequency of sonolysis, but was independent of the ultrasound intensity, at the plateau concentrations [J.Z. Sostaric, P. Riesz, Adsorption of surfactants at the gas/solution interface of cavitation bubbles: an ultrasound intensity-independent frequency effect in sonochemistry, J. Phys. Chem. B 106 (2002) 12537-12548]. In the current study, it was found that the CH(SPSo)/CH(SDS) ratio depended only on the ultrasound frequency and did not depend on the geometry of the ultrasound exposure apparatus considered. 相似文献
949.
We report a new long-term interferometric stabilization scheme for a delay line to be used for pump–probe spectroscopy on
the attosecond time scale. A separate interferometer with a He–Ne laser beam is used to stabilize the delay line with respect
to a slow drift in the optical delay induced mainly by ambient temperature changes in the laboratory. The power of the stabilization
scheme is demonstrated with the characterization of an attosecond pulse train in the extreme ultraviolet formed through high
order harmonic generation of Ti:sapphire laser radiation. We use the RABBITT technique for the attosecond pulse-train characterization
in a reaction microscope employed here for photoelectron–photoion-coincidence spectroscopy.
PACS 42.65.Ky; 42.65.Re; 07.60.Ly; 07.81.+a; 32.80.Fb 相似文献
950.
Extensive experimental results are presented to reveal the relaxations of polystyrene surface deformed by rubbing with a velvet
cloth. We found that surface topographic features, such as ditches and ridges created by rubbing, relax at temperatures at
about 20°
C below the bulk glass transition temperature of the polystyrene for a molecular weight of 442 kg/mol, even though we estimate
the Laplace Pressure driving the relaxation to be 1/500 of the yield limit. The relaxation is independent of the thermal history
before the rubbing process, and post rubbing thermal history below 55°
C . In other words, physical-aging processes at 23°
C for up to 7 days and at 50°
C for 2 days, which would have drastic effects on the relaxations of bulk polymers, have little effects on the relaxations
of rubbed surfaces. This is consistent with the mobility enhancement in the surface layer previously reported in the literature. 相似文献