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991.
Beker H. Bøggild H. Boissevain J. Cherney M. Dodd J. Esumi S. Fabjan C. W. Fields D. E. Franz A. Hansen K. H. Holzer B. Humanic T. Jacak B. Jayanti R. Kalechofsky H. Kobayashi T. Kvatadze R. Lee Y. Y. Leltchouk M. Lörstad B. Maeda N. Medvedev A. Miake Y. Miyabayashi A. Murray M. Nagamiya S. Nishimura S. Noteboom E. Pandey S. U. Piuz F. Polychronakos V. Potekhin M. Poulard G. Sakaguchi A. Sarabura M. Shigaki K. Simon-Gillo J. Sletten H. Sondheim W. Sugitate T. Sullivan J. P. Sumi Y. van Hecke H. Willis W. J. Wolf K. 《Zeitschrift fur Physik C Particles and Fields》1994,64(2):209-217
K+K+ and K–K– correlations from S+Pb collisions at 200 GeV/c per nucleon and K+K+ correlations from p+Pb collisions at 450 GeV/c per nucleon, are presented as measured by the focusing spectrometer of the NA44 experiment at CERN. Multidimensional fits are performed in order to characterize the kaon-emission volume, which is found to be smaller than the pion-emission volume. 相似文献
992.
993.
Blinov BB Chu CM Courant ED Crandell DA Kaufman WA Krisch A Nurushev TS Phelps RA Raczkowski DB Ratner LG Wong VK Caussyn DD Derbenev YS Ellison TJ Lee SY Rinckel T Schwandt P Sperisen F Stephenson EJ von Przewoski B Baiod R Minty MG Ohmori C Wienands U 《Physical review letters》1994,73(12):1621-1623
994.
995.
Growth of highly disordered InGaP on (100) GaAs by molecular beam epitaxy with a GaP decomposition source 总被引:1,自引:0,他引:1
High-quality, lattice-matched InGaP on exact (100) GaAs was successfully grown by molecular beam epitaxy with a GaP decomposition
source. The ordering parameter (η) of the InGaP is investigated as a function of the growth temperature. η is as low as 0.22
and almost insensitive to the growth temperature below 460 °C. It increases abruptly around 475 °C and has a maximum value
of 0.35 at ≈490 °C. Double crystal X-ray diffraction and a low-temperature photoluminescence spectrum reveal that the present
growth method is robust and provides better quality InGaP compared to other state-of-the-art growth technologies.
Received: 20 November 2000 / Accepted: 27 January 2001 / Published online: 21 March 2001 相似文献
996.
For decades the research on thin-film growth has attracted considerable attention as these kinds of materials have the potential for a new generation of device application. It is known that the nuclei at the initial stage of the islands are more stable than others and certain atoms are inert while others are active. In this paper, by using kinetic Monte Carlo simulations, we will show that, when a surfactant layer is used to mediate the growth, a counter-intuitive fractal-to-compact island shape transition can be induced by increasing deposition flux or decreasing growth temperature. Specifically, we introduce a reaction-limited aggregation (RLA) theory, where the physical process controlling the island shape transition is the shielding effect of adatoms stuck to the stable islands on the incoming adatoms. Moreover, the origin of a transition from triangular to hexagonal and then to inverted triangular as well as the decay characteristics of three-dimensional islands on the surface and relations of our unique predictions with recent experiments will be discussed. Furthermore, we will present a novel idea to make use of the condensation energy of adatoms to control the island evolution along a special direction. 相似文献
997.
Kellie Brown John Cameron John Stears Wayne Hicky Roger Cormier Xiaoyi Bao Liang Chen 《Fiber and Integrated Optics》2001,20(5):427-442
With OC-192 communications systems being commercially available and higher bit rate systems in development, prudent telecommunications network administrators are testing their installed fibers to determine if they can be successfully used at 10 Gb/s and higher. Together with New Brunswick Telephone (NBTel), the Fiber Optics Group at UNB have tested various installed fibers and cables in the NBTel network for their losses at wavelengths of 1244, 1310, 1550, and 1625 nm, as well as for strain and polarization mode dispersion (PMD). Weather conditions, age, place of installation, and cable types have also been considered. Aging does not seem to affect the performance of the fibers. Although most fibers are high-speed system compatible when looking at attenuation measurements, about 40% of the fibers tested would not meet the 10 Gb/s OC-192 system manufacturer's design guidelines concerning PMD. 相似文献
998.
We develop a stochastic formulation of cosmology in the early universe, after considering the scatter in the redshift-apparent
magnitude diagram in the early epochs as an observational evidence for the non-deterministic evolution of early universe.
We consider the stochastic evolution of density parameter in the early universe after the inflationary phase qualitatively,
under the assumption of fluctuating w factor in the equation of state, in the Fokker-Planck formalism. Since the scale factor for the universe depends on the energy
density, from the coupled Friedmann equations we calculated the two variable probability distribution function assuming a
flat space geometry. 相似文献
999.
Doo-Hee Chang Seung-Ho Jeong Bong-Guen Hong Kyu-Sun Chung Gon-Ho Kim Jae-Shin Lee 《Current Applied Physics》2001,1(6):497
The radial profiles of KT-1 tokamak (major radius of 27 cm, minor radius of 4.25 cm, two poloidal stainless-steel limiters) edge plasma parameters are measured using single and triple electric probes. The particle transport parameters are calculated from the measured edge plasma parameters, and the results are analyzed by the simple fluid approximations. The cross-field particle diffusion coefficient (D) in the boundary plasma of the KT-1 is calculated from the density scrape-off length (λn) measured by using a triple probe. The particle density and electron temperature fall exponentially in the radial direction with the e-folding length of λn=0.13 cm and λe=0.41 cm, respectively. From the scrape-off layer (SOL) model, the experimental values of scrape-off length (λn) is used to calculate the cross-field diffusion coefficient (D=1.2×103cm2/s), roughly corresponding to one third of the typical Bohm value. A simple SOL model with the contribution of recombination is introduced to evaluate the Bohm diffusion in the KT-1 tokamak edge plasma. Cross-field heat conductivity calculated from these deduced values is 5.2D in the SOL of KT-1 edge plasma. These results provide the finally certain information for edge particle transport in the KT-1 boundary plasmas. 相似文献
1000.
Hyun-Ju Chung Dong-Hoon Lee Do-Wan Kim Sung-Joon Park Yu-Soo Lee Jung-Hwan Hong Joong-Mann Kim Hee-Je Kim 《Optics & Laser Technology》2001,33(3):269
We propose a simple power supply for a longitudinally pulsed CO2 laser with long pulse duration by the switching control of AC line (60 Hz) on HV leakage transformer primary, which can generate long pulse of about 3 ms compared to a typical pulsed power supply. In this power supply, a low voltage open loop control for high voltage discharge circuit is employed to avoid the HV sampling or switching, and AC line voltage switched directly by a SCR is applied to the leakage transformer primary. Thus, there is no need of a rectified bridge and an energy-storage capacitor in the discharge circuit, and the leakage transformer allows one to omit a current-limiting resistor. In order to control the laser output power, the pulse repetition rate is adjusted up to 60 Hz. A ZCS circuit and a PIC one-chip microprocessor are used to control the gate signal of SCR precisely. 相似文献