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941.
The pulsed laser processing in liquid media is an attractive alternative to produce room temperature luminescent silicon nanocrystals (Si-ncs). We report on a blue luminescent Si-ncs preparation by using nanosecond pulsed laser (Nd:YAG, KrF excimer) processing in transparent polymer and water. The Si-ncs fabrication is assured by ablation of crystalline silicon target immersed in liquids. During the processing and following aging in liquids, oxide based liquid media, induce shell formation around fresh nanocrystals that provides a natural and stable form of surface passivation. The stable room temperature blue-photoluminescent Si-ncs are prepared with maxima located around ∼440 nm with corresponding optical band gap around ∼2.8 eV (∼430 nm). Due to the reduction of surface defects, the Si-ncs preparation in water, leads to a narrowing of full-width-half-maxima of the photoluminescence spectra. 相似文献
942.
K.Kawase M.Kando T.Hayakawa I.Daito S.Kondo T.Homma T.Kameshima H.Kotaki L.Chen Y.Fukuda A.Faenov Shizuma S.V.Bulanov T.Kimura T.Tajima M.Shoji S.Suzuki K.Tamura H.Ohkuma Y.Arimoto T.Yorita M.Fujiwara S.Okajima 《原子核物理评论》2009,26(Z1)
Recently we have constructed two facilities for generating photon beams in the MeV and sub-MeV energy regions by means of the Compton backscattering with a laser and an electron beam at SPring-8 and at Kansai Photon Science Institute of Japan Atomic Energy Agency(KPSIJAEA).The MeV-photon source at SPring-8 consists of a continuous-wave optically-pumped far infrared laser with a wavelength of 118.8 μm and an 8 GeV stored electron beam.Present MeV-photon flux is estimated to be 1.3×10~3 photons/s.On the other hand,the sub-MeV-photon source at KPSI-JAEA consists of a pulse Nd:YAG laser with a wavelength of 1 064 nm and a 150 MeV electron beam accelerated by microtron.In the first trial of the photon production in this source,backscattered photon flux is estimated to be 20 photons/pulse.Both the Compton backscattered photon sources have possibilities to be used for new tools in various fields such as nuclear physics,materials science,and astronomy. 相似文献
943.
Junji Awaka Norihito Kijima Shoichi Nagata 《Journal of Physics and Chemistry of Solids》2008,69(7):1740-1746
High-purity powder specimens of AgCa2Mn2V3O12 and NaPb2Mn2V3O12 have been successfully synthesized by solid-state chemical reaction. The Rietveld refinements from X-ray powder diffraction data verified that these compounds have the garnet-type structure (space group , No. 230) with the lattice constant of a=12.596(2) Å for AgCa2Mn2V3O12 and a=12.876(2) Å for NaPb2Mn2V3O12. Calculation of the bond valence sum supported that Mn is divalent and V is pentavalent in these garnets. Estimation of the quadratic elongation and the bond angle variance showed that the distortions of the MnO6 octahedra and the VO4 tetrahedra are significantly suppressed. Our new results of AgCa2Mn2V3O12 and NaPb2Mn2V3O12 are compared to those of AgCa2M2V3O12 and NaPb2M2V3O12 (M=Mg, Co, Ni, Zn). 相似文献
944.
Rushford MC Britten JA Barty CP Jitsuno T Kondo K Miyanaga N Tanaka KA Kodama R Xu G 《Optics letters》2008,33(16):1902-1904
We introduce a four-pass laser pulse compressor design based on two grating apertures with two gratings per aperture that is tolerant to some alignment errors and, importantly, to grating-to-grating period variations. Each half-beam samples each grating in a diamond-shaped compressor that is symmetric about a central bisecting plane. For any given grating, the two half-beams impinge on opposite sides of its surface normal. It is shown that the two split beams have no pointing difference from paired gratings with different periods. Furthermore, no phase shift between half-beams is incurred as long as the planes containing a grating line and the surface normal for each grating of the pair are parallel. For grating pairs satisfying this condition, gratings surfaces need not be on the same plane, as changes in the gap between the two can compensate to bring the beams back in phase. 相似文献
945.
Danno D Kanno M Fujimoto S Feril LB Kondo T Nakamura S 《Ultrasonics sonochemistry》2008,15(4):463-471
AIM: The present study was conducted to examine the thermal and non-thermal effects of ultrasound on apoptosis induced by anti-CD20 monoclonal antibody (rituximab). MATERIALS AND METHODS: SU-DHL-4 cells, a CD20-positive cell line derived from B cell lymphomas with a BCL2 gene rearrangement, were exposed to continuous 1 MHz ultrasound for therapeutic use under an air- or CO(2)-saturated condition to control cavitation. Early apoptosis (EA) and secondary necrosis (SN) were examined by flow cytometry. Cavitation was determined by detecting the hydroxyl radicals derived from pyrolysis of water molecules using electron paramagnetic resonance-spin trapping. To assess thermal effects, cells were treated in a temperature-controlled water bath. RESULTS: There was a significant additive increase in EA and EA+SN observed in cells treated with rituximab combined with heat at 42 degrees C or non-thermal ultrasound at 0.5 W/cm(2) under an air-saturated condition, where heat or ultrasound induced some cell death. A significant synergistic increase in EA and EA+SN was observed in cells treated with rituximab and ultrasound at 2.5 W/cm(2) under CO(2)-saturated conditions, where inertial cavitations were completely suppressed. No enhancement was observed at a temperature less than 40 degrees C or ultrasound at 0.5 W/cm(2) under CO(2)-saturated conditions. CONCLUSION: These results suggest that the immuno-therapeutic application of ultrasound at relatively high-intensities combined with rituximab thus produces synergistic effects under conditions where the non-thermal and non-cavitational effects are predominant. 相似文献
946.
947.
948.
N. Matsuoka K. Hatanaka M. Fujiwara Y. Fujita T. Saito K. Hosono A. Shimizu M. Kondo F. Ohtani H. Sakaguchi A. Goto N. Nakanishi Y. Toba 《Nuclear Physics A》1982,373(3):377-396
Differential cross sections of 3He elastic scatterings and (3He, d) reactions have been measured at 90 MeV for 28Si, 54Fe, 58Ni, 90Zr and 124Sn. From the optical-model analysis of the elastic scattering, both shallow () and deep () potentials of 3He were obtained. The shallow potentials correspond to the ones which were determined uniquely from other measurements extended to more backward angles. The (3He, d) reactions have been analyzed with the DWBA using the shallow and deep potentials for 3He. The calculations using the deep potentials reproduced the data well, but those using the shallow ones did not. The contributions from the nuclear interior were investigated through the radial cutoff in the DWBA. The calculations using the shallow potentials reproduced the data well when the radial cutoffs were introduced. The effects of the radial cutoff were very small when the deep potentials were used. It was found that a much greater reduction of the contributions from the nuclear interior was needed when the shallow potentials were used in the DWBA calculations. 相似文献
949.
950.