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51.
We prove non-existence of smooth solutions of a quasi-linear system suggested by Ericksen in a model of Non-linear Elasticity. This system is of mixed elliptic–hyperbolic type. We discuss also a relation of such a system to polynomial integrals of Classical Hamiltonian systems. 相似文献
52.
Hydrogenated amorphous silicon (a‐Si:H) films were studied using infrared and Raman spectroscopy. We have experimentally found that ratios of Raman scattering cross‐sections for Si–H to Si–Si bonds and for Si–H2 to Si–Si bonds are equal to 0.65 ± 0.07 and 0.25 ± 0.03, respectively. It allows to measure the concentration of hydrogen in a‐Si:H films. The developed approach can be applied for in situ control of hydrogen in a‐Si:H films and also suitable for thin a‐Si:H films on substrates that are opaque in infrared spectral region. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
53.
Hua J Xiao ZL Imre A Yu SH Patel U Ocola LE Divan R Koshelev A Pearson J Welp U Kwok WK 《Physical review letters》2008,101(7):077003
We investigated confinement effects on the resistive anisotropy of a superconducting niobium strip with a rectangular cross section. When its transverse dimensions are comparable to the superconducting coherence length, the angle dependent magnetoresistances at a fixed temperature can be scaled as R(theta,H) = R(H/Hctheta) where Hctheta =Hc0(cos2theta + gamma(-2)sin2theta)(-1/2) is the angular dependent critical field, gamma is the width to thickness ratio, and Hc0 is the critical field in the thickness direction at theta=0 degrees . The results can be understood in terms of the anisotropic diamagnetic energy for a given field in a one-dimensional superconductor. 相似文献
54.
A. S. Koshelev L. Ye. Dovbysh V. Kh. Khoruzhy S. V. Chuklyaev 《Physics of Atomic Nuclei》2015,78(11):1206-1212
The construction of the KGK-2-type detector of γ-radiation power is briefly described. The diagnostic possibilities of the detector are shown by the example of results of the dose rate measurement in the energy start-ups of the BR-K1 and BR-1M reactors implemented in the mode of generating fission pulses on delayed neutrons. The possibilities of using the KGK-2 detector for postpulse γ diagnostics are demonstrated by the example of results of measurements in the fission pulse on prompt neutrons of the BR-1M reactor. 相似文献
55.
A. S. Koshelev L. Ye. Dovbysh M. A. Ovchinnikov G. N. Pikulina Yu. M. Drozdov S. V. Chuklyaev Yu. N. Pepyolyshev 《Physics of Atomic Nuclei》2017,80(8):1348-1356
The design of the fast neutron detector KNK-2-8M is outlined. The results of he detector study in the pulse counting mode with pulses from 238U nuclei fission in the radiator of the neutron-sensitive section and in the current mode with separation of functional section currents are presented. The possibilities of determination of the effective number of 238U nuclei in the radiator of the neutron-sensitive section are considered. The diagnostic capabilities of the detector in the counting mode are demonstrated, as exemplified by the analysis of reference data on characteristics of neutron fields in the BR-1 reactor hall. The diagnostic capabilities of the detector in the current mode are demonstrated, as exemplified by the results of measurements of 238U fission intensity in the power startup of the BR-K1 reactor in the fission pulse generation mode with delayed neutrons and the detector placed in the reactor cavity in conditions of large-scale variation of the reactor radiation fields. 相似文献
56.
A locally conformally Kähler (LCK) manifold is a complex manifold admitting a Kähler covering, with the monodromy acting on this covering by holomorphic homotheties. We define three cohomology invariants, the Lee class, the Morse–Novikov class, and the Bott–Chern class, of an LCK-structure. These invariants play together the same role as the Kähler class in Kähler geometry. If these classes coincide for two LCK-structures, the difference between these structures can be expressed by a smooth potential, similar to the Kähler case. We show that the Morse–Novikov class and the Bott–Chern class of a Vaisman manifold vanish. Moreover, for any LCK-structure on a manifold, admitting a Vaisman structure, we prove that its Morse–Novikov class vanishes. We show that a compact LCK-manifold M with vanishing Bott–Chern class admits a holomorphic embedding into a Hopf manifold, if dimCM?3, a result which parallels the Kodaira embedding theorem. 相似文献
57.
V. A. Morozova O. G. Koshelev E. P. Veretenkin V. N. Gavrin Yu. P. Kozlova 《Moscow University Physics Bulletin》2009,64(2):177-181
Photo-emf in the range hv = 0.76 ? 1.35 eV was found in p-i-n structures produced from undoped GaAs crystals with known parameters; the current sensitivities in the impurity and intrinsic (hv > 1.35 eV) regions were comparable. It was proven that the impurity photovoltaic effect results from EL2 and EL3 structural defects creating deep donor levels in the forbidden zone. Calculations were performed that justified the possibility of observing this effect on the investigated structures. 相似文献
58.
I. V. Aleksandrova E. L. Koshelev A. I. Nikitenko T. P. Timasheva E. R. Koresheva 《Journal of Russian Laser Research》2018,39(2):140-155
Creation of a delivery system based on noncontact positioning and transport of the cryogenic fuel targets represents one of the major tasks in a general program of inertial fusion energy (IFE) research. The purpose is to maintain the fuel layer quality during acceleration and injection of IFE targets at the focus of a powerful laser facility or IFE reactor. The program of the Lebedev Physical Institute (LPI) includes much development work on creation of different designs of the hybrid accelerators for IFE target transport with levitation. One of the main directions is an electromagnetic accelerator (EM-AC) + PMG system, where PMG is the permanent magnet guideway. The operational principle is based on quantum levitation of type-II high-temperature superconductors (HTSC) in the magnetic field. At the current stage, conceptual development of “EM-AC + PMG” hybrid accelerator is complete, and proof-of-principle experiments in mutually normal magnetic fields are made. This accelerator is a combination of the acceleration system (field coils generating the traveling magnetic waves) and the levitation system (PMG including a magnetic rail or magnetic track). The results obtained show that the HTSCs can be successfully used to maintain friction-free motion of HTSC sabots over the PMG, and also provide the required stability of the levitation height over the whole acceleration length due to the pinning effect. Additionally, using the driving body from MgB2 superconducting coils as a sabot component (critical current 5,000 A at magnetic induction 0.25 T) allows one to reach injection velocities of 200 m/s under 400 g at 5 m acceleration length. 相似文献
59.
The aim of this article is to study the asymptotic behavior for large times of solutions of linear stochastic partial differential equations of parabolic type. In particular, we will prove the backward uniqueness result and the existence of the spectral limit for abstract SPDEs and then show how these results can be applied to linear SPDEs. 相似文献
60.
Medvedev VV Yakshin AE van de Kruijs RW Krivtsun VM Yakunin AM Koshelev KN Bijkerk F 《Optics letters》2012,37(7):1169-1171
An extreme ultraviolet multilayer mirror with an integrated spectral filter for the IR range is presented and experimentally evaluated. The system consists of an IR-transparent B4C/Si multilayer stack which is used both as EUV-reflective coating and as a phase shift layer of the resonant IR antireflective (AR) coating. The AR coating is optimized in our particular case to suppress CO2 laser radiation at a wavelength of 10.6 μm, and a suppression of more than two orders of magnitude is demonstrated. The method allows high suppression over a large angular acceptance range, relevant for application in lithography systems. 相似文献