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D. J. SINGH A. KUMAR S. N. TIWARI 《International Journal of Computational Fluid Dynamics》2013,27(3):177-196
A numerical study is conducted to simulate the effects of extraneous shock impingement on a blunt body in viscous hypersonic flow. The interaction of extraneous shock with the leading-edge shock results in a very complex flow field that contains local regions of high pressure and intense heating. The heating and pressure can be orders of magnitude higher than the peak values in the absence of shock impingement. The flow field is calculated by solving thin-layer Navier-Stokes equations with a finite-volume flux splitting technique developed by van Leer. For a zero or small sweep of the body, a type IV interaction occurs, which produces a lambda shock structure with a supersonic jet embedded in the otherwise subsonic flow; for a moderate sweep of about 25°, a type V interaction occurs in which a subsonic shear layer sandwiched in supersonic flow is produced with a transmitted shock. In the present study, both type IV and type V interactions are investigated. Results of the present numerical investigation are compared with available experimental results. For the present conditions, the peak pressure is 2.2 times the unimpinged stagnation point pressure and the peak heating is 3 times the unimpinged stagnation point heating. The flow for a type IV interaction is found to be unsteady. 相似文献
73.
Monte Carlo N-particle (MCNP) code has been used to simulate the transport of gamma photon rays of different energies (22, 31, 59.5 and 81 keV) to estimate the iron content in solutions. In this study, MCNP simulation results are compared with experiment and XCOM theoretical data. The simulation shows that the obtained results are in good agreement with experimental data, and better than the theoretical XCOM values. The study indicates that MCNP simulation is an excellent tool to estimate the iron concentration in the blood samples. The MCNP code can also be utilized to estimate other trace elements in the blood samples. 相似文献
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ALOK SRIVASTAVA TEJVIR SINGH AMIT LOCHAN SHARMA P.K. JAIN S. PONRATHNAM C. R. RAJAN 《辐射效应与固体损伤》2013,168(8):561-566
The commercially available solid state nuclear track detector CR-39 was bombarded with 100 MeV Si8+ ions. The Fourier transfonned infrared (FTIR) spectroscopic technique was employed for studying the changes in chemical properties whereas differential scanning calorimetry was used for studying the changes in thermal properties. It was observed that there were substantial chemical modifications in the sample, such as the breaking of C-0 single bonds and the formation of phenolic 0-H bonds. lt was further observed that CR-39 is amorphous and rigid and shows no glass transition temperature. 相似文献
77.
Fission fragments and other charged particles leave tracks of permanent damage in most of the insulating solids. Damage track
detectors are useful for personal dosimeters and for flux/dose determination of high-energy particles from accelerators or
cosmic rays. A detector that has its principal response at nucleon energy above 50 MeV is provided by the fission of Bi-209.
Neutrons produce the largest percentage of hadron dose in most high-energy radiation fields. In these fields, the neutron
spectrum is typically formed by low-energy neutrons (evaporation spectrum) and high-energy neutrons (knock-on spectrum). We
used Bi-fission detectors to measure neutron peak fluence and compared the result with the calculated value of neutron peak
fluence. For the exposure to 100 MeV we have used the iThemba Facility in South Africa. 相似文献
78.
We use rationalization method to study two-dimensional complex dynamical systems (shifted harmonic oscillator in complex plane) on the extended complex phase space (ECPS). The role and scope of the derived invariants in the context of various physical problems are highlighted. 相似文献
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Development of a discharge-pumped krypton chloride (KrCl) laser operating at 222 nm wavelength is demonstrated. In this paper the design, successful realization and operating characteristics of KrCl excimer laser are reported. The laser is driven by a simple and efficient excitation technique using automatic UV pre-ionization with discharge-pumped self-sustained capacitor–capacitor (C–C) energy transfer circuit. The experimental investigations including output laser energy, temporal pulse parameters, emission spectra and beam profile of the KrCl laser were recorded. For high repetition rate operation, in-built, compact gas circulation system using tangential blower was incorporated. The laser was operated at 25 kV discharge voltage, gas mixture of 5 mbar HCl, 160 mbar kypton and neon as balance with a total gas pressure of ~2.5 bar. These experiments produced an efficient and reliable output energy of 25 mJ from an active volume of 60 cm3. 相似文献