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1.
5‐Amino‐4‐methyl‐2‐phenyl‐6‐substitutedfuro[2,3‐d]pyrimidines ( 2a‐c ) were reacted with 2,5‐dimethoxytetrahydrfuran to afford the pyrrolyl derivatives 3a‐c . Compound 3a was chosen as intermediate for the synthesis of poly fused heterocycles incorporated furopyrimidines moiety 4–11 . Some of the synthesized compounds were screened for their antibacterial and antifungal activities. 相似文献
2.
Numerical simulation aspects, related to low Reynolds number free boundary viscous flows at micro and mesolevel during the resin impregnation stage of the liquid composite moulding process (LCM), are presented in this article. A free boundary program (FBP), developed by the authors, is used to track the movement of the resin front accurately by accounting for the surface tension effects at the boundary. Issues related to the global and local mass conservation (GMC and LMC) are identified and discussed. Unsuitable conditions for LMC and consequently GMC are uncovered at low capillary numbers, and hence a strategy for the numerical simulation of such flows is suggested. FBP encompasses a set of subroutines that are linked to modules in ANSYS. FBP can capture the void formation dynamics based on the analysis developed. We present resin impregnation dynamics in two dimensions. Extension to three dimensions is a subject for further research. Several examples are shown and efficiency of different stabilization techniques are compared. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Braverman Michael SH.; Stepanov Vladimir D. 《Bulletin London Mathematical Society》1994,26(3):283-287
Necessary and sufficient conditions for the boundedness of thediscrete Hardy operator of the form , from to when 0 < q < 1 <p , is given. 相似文献
5.
Andr Bnard Suresh G. Advani Jerold M. Schultz 《Journal of Polymer Science.Polymer Physics》1996,34(3):471-483
Solidification of semicrystalline materials often occurs in significantly undercooled melts. The crystal growth process in such melts is convoluted due to the fact that the interface between the solid and liquid domains of the microscopic crystals is at an unknown temperature. However, it is possible to let the temperature of this interface be unspecified and solve the problem with a semianalytical method if the growth velocity is prescribed. Solutions for the temperature profiles in both solid and liquid phases are presented in this work, along with the interface temperature, for phase change processes controlled by the kinetics of crystallization rather than diffusion processes, which is typical for polymers. The method is used for one-dimensional problems in cartesian, cylindrical, and spherical geometries that correspond to commonly found microstructures. It is found that the temperature of the interface is significantly below the equilibrium melting point and a quasi steady-state regime is reached rapidly. Comparison with the classical Neumann's solution shows that the temperature profiles are similar but the position of the interface differs considerably. © 1996 John Wiley & Sons, Inc. 相似文献
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SHUbarICHI NOSÉ 《Molecular physics》2013,111(1):191-198
A molecular dynamics simulation method which can generate configurations belonging to the canonical (T, V, N) ensemble or the constant temperature constant pressure (T, P, N) ensemble, is proposed. The physical system of interest consists of N particles (f degrees of freedom), to which an external, macroscopic variable and its conjugate momentum are added. This device allows the total energy of the physical system to fluctuate. The equilibrium distribution of the energy coincides with the canonical distribution both in momentum and in coordinate space. The method is tested for an atomic fluid (Ar) and works well. 相似文献
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Advani R. Hogge J.P. Kreischer K.E. Pedrozzi M. Read M.E. Sirigiri J.R. Temkin R.J. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2001,29(6):943-950
We report experimental results on a megawatt power level, 140-GHz coaxial gyrotron oscillator. The gyrotron has an inverted magnetron injection gun (IMIG) designed for operation at up to 95 kV and 88 A. The IMIG has an inner grounded anode which extends from the center of the gun down through the entire length of the tube including the cavity and collector. The IMIG was tested at up to 105 kV and 93 A in 3 μs pulses, achieving an electron beam power of 10 MW. The output power from the coaxial gyrotron cavity was transported to an internal mode converter and a single mirror that coupled the power out transversely from the tube axis. A maximum output power of up to 1 MW was obtained in the TE27,11 mode at 142 GHz at an efficiency of 16%, about one half of the design efficiency. The reduced efficiency was attributed to nonuniformity of the cathode emission and the sensitivity to the relative alignment of the electron gun, coaxial insert, and cavity. The cathode emission over the azimuthal angle was measured for two cathodes and was shown to be nonuniform due to both temperature and emitter work function nonuniformity. The gyrotron was also tested in two alternate configurations: 1) with the internal mode converter removed (axial output), and 2) with both the internal converter and the coaxial insert removed (empty cavity). In operation in the empty cavity configuration, which is equivalent to a conventional gyrotron oscillator, output power of up to 0.9 MW was observed 相似文献
10.
Metal/superconductor/semiconductor (Ag/Hg-1212/CdSe) hetero-nanostructures have been fabricated using pulse-electrodeposition
technique and are characterized by X-ray diffraction (XRD), full-width at half-maximum (FWHM) and scanning electron microscopy
(SEM) studies. The junction capacitance of Ag/Hg-1212, Hg-1212/CdSe and Ag/Hg-1212/CdSe heterojunctions is measured in dark
and under laser irradiation at room temperature. The nature of the junction formed and built-in-junction potentials were determined.
The increase in carrier concentration across the junction due to photo-irradiation has been observed. 相似文献