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51.
The structure of 1,3-dehydro-5-adamantyl cation and its isoelectronic boron analogue 1,3-dehydro-5-boraadamantane as well as some related adamantane systems, hitherto unknown as persistent long-lived species, were investigated by using the density functional theory (DFT) method. (13)C and (11)B NMR chemical shifts of the compounds were also calculated using the IGLO method. Stabilization of the systems due to homoconjugation is discussed. 相似文献
52.
53.
Romesh Chandra Boruah Purabi Devi J. S. Sandhu 《Journal of heterocyclic chemistry》1979,16(8):1555-1557
Some 7-melhyl-substituted-2,1-benzisoxazoles and cyclopropanobenzofurazan oxides are synthesized and characterized by their elemental and spectral analyses. 相似文献
54.
Romesh Chandra Boruah J. S. Sandhu G. Thyagarajan 《Journal of heterocyclic chemistry》1979,16(5):1087-1088
Novel reductive chlorination of 3-aryl-2,1-benzisoxazoles with thionyl chloride is described. The chlorinated aminobenzophenones have been characterised. 相似文献
55.
56.
GK Johri Akhilesh Tiwari Saumya Saxena Rajesh Sharma Kuldeep Srivastava Manoj Johri 《Pramana》2002,58(3):563-567
Calculations for the relative width (Δω/ω0) as a function of refractive index and relative radius of the photonic band gap for the fcc closed packed 3-D dielectric
microstructure are reported and comparison of experimental observations and theoretical predictions are given. This work is
useful for the understanding of photonic crystals and occurrence of the photonic band gap. 相似文献
57.
We calculate the neutron-evaporation residue cross sections σ 3n , σ 4n , and σ 5n in the hot-fusion reactions 48Ca+242,244Pu →290,292114 ? over a wide range of compound-nucleus excitation energies ( $E_{\text{CN}}^{*}$ = 34–53 MeV). We work with the dynamical cluster-decay model (DCM), with a single parameter, the neck-length parameter ΔR. To calculate neutron-evaporation cross sections, we choose the superheavy proton magic Z = 126 and neutron magic N = 184. Among the 3n, 4n, and 5n production cross sections for 290, 292114?, only the 3n decay cross sections of 292114? correspond to spherical fragmentation. The 4n and 5n cross sections of 292114? and 3n, 4n, and 5n cross sections of 290114? could only be fitted after the inclusion of quadrupole deformations β 2i within the optimum orientation approach. Changes in the angular momentum and N/Z ratio do not significantly influence the fragmentation paths of 290, 292114? superheavy nuclei. Larger barrier modification is required for the lower angular momentum states and lighter neutron clusters. The contribution of the fusion–fission component is also computed for the compound nucleus 292114? in the energy range $E_{\text{CN}}^{*}$ = 27–47 MeV. 相似文献
58.
M. P. Singh Amandeep Sharma Bhajan Singh B. S. Sandhu 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):187-194
The effective atomic numbers of composites and Rayleigh-to-Compton cross-section ratio of elements, in the range 6 ≤ Z ≤ 82 for 145 keV gamma photons, are determined experimentally. An HPGe (high purity germanium) semiconductor detector is placed, at scattering angle of 90°, to record the spectra originating from interactions of incident gamma photons with the target under investigations. The intensity ratio of Rayleigh-to-Compton scattered peaks, corrected for photo-peak efficiency of gamma detector and absorption of photons in the target and air column, is plotted as a function of atomic number and a best fit-curve is constituted. From this fit-curve, the respective effective atomic numbers of the scientific samples are determined. The measured values of cross-section ratio increases non-linearly with increase in atomic number and are found to agree with theoretical predictions based upon non-relativistic form factor, relativistic form factor, modified form factor and S-matrix theory. 相似文献
59.
Huo Y Sandhu S Pan J Stuhrmann N Povinelli ML Kahn JM Harris JS Fejer MM Fan S 《Optics letters》2011,36(8):1482-1484
We measure the group delay in an on-chip photonic-crystal device with two resonators side coupled to a waveguide. We demonstrate that such a group delay can be controlled by tuning either the propagation phase of the waveguide or the frequency of the resonators. 相似文献
60.
Benzofuroxan reacts with imines derived from crotonaldehyde and cinnamaldehyde, to form 2-imino-methylquinoxaline 1,4-dioxides. 相似文献