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971.
972.
Cyclic voltammetric studies of certain industrially potential iron chelate catalysts 总被引:1,自引:0,他引:1
For the analysis of infrared spectroscopic bands and complex patterns partial cross correlation functions of a sample spectrum
with reference spectra are calculated. The chosen ranges of the spectra are based on empirical knowledge of infrared spectrum
structure correlations. The normalised maxima of the partial cross correlation functions are interpreted as fuzzy truth values
and are combined by fuzzy logical operators. By application of that procedure larger common substructures will be derived
from the reference spectra than by a maximum common substructure search based on the complete spectra.
Received: 30 October 1996/Revised: 24 February 1997/Accepted: 26 February 1997 相似文献
973.
By noting changes in the color of samples in a polarization microscope with varying degree of birefringence, the effect of
a weak static magnetic fields (2 and 4 kOe) on molecules of glassy polymers has been observed. Variations in the nonmonotonicity
of the rate of discontinuous creep at +18° were studied interferometrically. It is shown that the abruptness of the deformation
jumps varies in a magnetic field, where this abruptness is assumed to be due to the existence of strong physical junctions
between the kinetic units of deformation. The reactivity of the polymers to the magnetic field stands in satisfactory correspondence
with their magnetic susceptibilities. Results show that such nonmagnetic materials as glassy polymers can noticeably alter
their deformational properties in response to the action of magnetic fields.
Fiz. Tverd. Tela (St. Petersburg) 39, 1690–1692 (September 1997) 相似文献
974.
It was shown by G. A. Jones and the first author in [8] that underlying any map on a compact orientable surface S there is a natural complex structure making S into a Riemann surface. In this paper we consider regular maps and enquire about the Weierstrass points on the underlying Riemann surface. We are particularly interested to know when these are geometric, i.e. whether they lie at vertices, face-centres or edge-centres of the map. 相似文献
975.
Distribution of melamine in polyester–melamine surface coatings cured under nonisothermal conditions
N. J. W. Gamage D. J. T. Hill C. A. Lukey P. J. Pomery 《Journal of polymer science. Part A, Polymer chemistry》2004,42(1):83-91
The influence of experimental cure parameters on the diffusion of reactive species in polyester–melamine thermoset coatings during curing has been investigated with X‐ray photoelectron spectroscopy and attenuated total reflectance Fourier transform infrared. The diffusion of melamine plays a vital role in the curing process and, therefore, in the ultimate properties of coatings. At a low (<20%) hexamethoxymethylmelamine (HMMM) crosslinker concentration, the matrix composition is uniform, but at high HMMM concentrations, excess HMMM rapidly segregates to the air–coating interface. The rate of migration is governed by the difference in the surface free energies of polyester and HMMM and the concentration gradient of HMMM between the bulk and the surface. An increased rate of energy absorption also increases the rate of migration of HMMM to the surface. A physical model has been proposed to explain this surface segregation phenomenon in terms of cocondensation and self‐condensation reactions. It suggests that an appropriate amount of melamine can be segregated on the surface and allowed to self‐condense to form a desired thickness of a melamine topcoat through the control of the binder composition and cure conditions. This technique can be implemented to apply a melamine topcoat during cure. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 83–91, 2004 相似文献
976.
Dilek Yildiz JeronimusP.A.J. vanBeeck MichelL. Riethmuller 《Particle & Particle Systems Characterization》2004,21(5):390-402
Two‐phase flows hold an interest in many areas of science and engineering. In the safety field, one such topic is the accidental release of flammable and toxic pressure‐liquefied gases. In case of such a release, a flashing vapor explosion takes place resulting in a very dense two‐phase cloud. If the released substance is flammable, this cloud can be combustible and can lead to deflagration or detonation. For understanding the source processes of flashing and risk assessment, data related to cloud characteristics (i.e. droplet size, velocity etc.) is needed especially in the near region of the release. Due to the non‐equilibrium nature of the near field regions accurate data measurement is not possible with intrusive techniques. Therefore, laser‐based optical techniques (like Particle Image Velocimetry (PIV), Particle Tracking Velocimetry and Sizing (PTVS), Phase Doppler Anemometry (PDA) etc.) present the only possibility to obtain information for particle diameter and velocity evolution in this harsh environment. 相似文献
977.
R. López-Martens J. Mauritsson P. Johnsson K. Varjú A. L’Huillier W. Kornelis J. Biegert U. Keller M. Gaarde K. Schafer 《Applied physics. B, Lasers and optics》2004,78(7-8):835-840
We characterize the temporal structure of high-order harmonic radiation on both the femtosecond and attosecond time scales. The harmonic emission is characterized by mixed-color two-photon ionization with an infrared femtosecond laser using a Mach–Zehnder interferometer where both pump and probe arms travel completely separate paths. In a first experiment, we measure the duration and chirp of individual harmonics. In a second experiment, we resolve, for the first time with this type of setup, the attosecond beating of several harmonics generated under conditions similar to the first experiment. We suggest that the results of both measurements can be combined to determine the full attosecond time structure of the harmonic emission. PACS 32.80.Rm; 42.65.Ky 相似文献
978.
The magnetic and electric properties of the Sr2FeMoO6 compound produced under different preparation conditions were studied. Depending on the preparation condition, a strong variation in the nonmagnetic SrMoO4 impurity content was found, which in turn determined the metallic or semiconducting behavior of the resistivity of the Sr2FeMoO6 compound. There was also evidence that SrMoO4 played a crucial role in modifying the low magnetic field intergrain tunneling magnetoresistance in Sr2FeMoO6. In addition, we have established a simple method to prepare the single phase Sr2FeMoO6 polycrystals. 相似文献
979.
S. S. Stavitskaya N. T. Kartel’ N. N. Tsyba M. F. Kovtun T. P. Petrenko 《Russian Journal of Applied Chemistry》2007,80(3):379-385
The mineral and chemical compositions, as well as some structure-sorption characteristics were determined for clay minerals selected for examination. The integrated coefficients of contamination of bottom sediments with each of the toxicant metals (Fe, Ni, Co, Cu, Zn, Pb, Mn) were calculated. The minerals examined presumably can be used in medicine as efficient application materials, cosmetic agents, and sorbents (enterosorbents). 相似文献
980.