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1.
N. A. Sivov A. I. Martynenko G. N. Bondarenko M. P. Filatova E. Yu. Kabanova N. I. Popova A. N. Sivov E. B. Kruts’ko 《Petroleum Chemistry》2006,46(1):41-59
Structures and compositions of the monomers guanidine acrylate and guanidine methacrylate, their homopolymers, and copolymers with diallyldimethylammonium chloride enriched in acrylate comonomer units were determined. It was shown that ampholytic copolymers, owing to their ionic nature, contained comonomeric guanidine acrylate or methacrylate units and diallyldimethylammonium chloride units, as well as the acrylate comonomer with the diallyl counterion and polymeric acrylate and diallyl ion pairs. It follows from IR and 1H NMR data that guanidine methacrylate has the same structure (with two hydrogen bonds) in the solid state and in solutions. Guanidine acrylate structures in the solid state and in dimethylsulfoxide are identical and analogous to guanidine methacrylate structure in this solvent. In water, the guanidine acrylate structure has another type of hydrogen bonding (with one hydrogen bond, where the proton is shifted toward the guanidine group). These features of hydrogen bonding of guanidine acrylate and guanidine methacrylate are also retained in their homopolymers and copolymers with diallyldimethylammonium chloride. It was shown that the thermal stability of the copolymers was higher than that of their homopolymers, confirming the formation of intramolecular ion pairs of oppositely charged units of ampholytic copolymers. Moreover, the thermal stability of guanidine methacrylate-diallyldimethylammonium chloride copolymers is higher than that of guanidine acrylate-diallyldimethylammonium chloride copolymers. 相似文献
2.
3.
O. A. Teplov I. G. Voropaev V. G. Dyubanov L. I. Leont’ev 《Russian Metallurgy (Metally)》2007,(4):268-275
The interaction of hydrogen with the zinc-containing electrometallurgical slime of the Severstal’ metallurgical works has been studied. The sequence of transformations in the slime heated to 1100°C in hydrogen or air has been established. The experimental and calculated weight losses coincide. Some of the carbonates are shown to decompose in the temperature range 300–700°C, and most iron and zinc oxides are reduced to a metal. In the temperature range 650–850°C, zinc is almost completely sublimated. At temperatures above 800°C, complex oxides are reduced and calcium and magnesium carbonates and sulfates are likely to decompose. Experimental digital data on the zinc sublimation rate are processed by the least squares method with approximating equations used in thermal analysis. The kinetics of nonisothermal zinc sublimation is comprehensively analyzed using a unique procedure developed for taking into account the background of a peak and the effect of accompanying processes. An equation for the calculation of the zinc sublimation rate under experimental conditions (fluidized bed) is given and tested. 相似文献
4.
Thin-film nickel coatings on fiber materials 总被引:1,自引:0,他引:1
L. M. Lyn’kov V. A. Bogush E. A. Senkovets S. M. Zavadskii 《Technical Physics Letters》2003,29(8):641-642
Vacuum deposition of thin films onto fiber materials is a promising method of obtaining electromagnetic screens. We have studied the structure and the electromagnetic properties of machine-knitted fabric coated with nickel by means of magnetron sputtering. When the fabric is irradiated from the metal-coated side, the reflection coefficient is higher by a factor of 1.4 as compared to the case when the same source of electromagnetic radiation is situated on the opposite side (facing the uncoated surface), while the absorption coefficient in both cases is the same. 相似文献
5.
6.
Li Xi Zuoyan Peng Wei Fan Kui Guo Gu Jianmin Muyu Zhao Wu Guoqiang 《Materials Science and Engineering: B》1996,40(2-3):147-152
SrMgxTi1 - xO3 nanocrystals (x = 0.1–0.6) were synthesized by the stearic acid gel method. Powder samples were characterized by X-ray diffraction and X-ray photoelectron (XP) spectroscopy. The results showed that the lattice parameter a and the O 1s XP spectrum changed not only with the Mg content x but also with the grain size d of the samples. The conductivity of a thick film specimen fabricated on an aluminium oxide wafer was investigated in a nitrogen—oxygen atmosphere. 相似文献
7.
Porous silica glass was prepared by sol-gel process from tetraethoxysilane (TEOS). The effects of solvents (water, ethanol), drying condition, heat treatment temperature on specific surface area and pore size distribution of porous silica were investigated. Gelation process accelerates with an increase of H2O content, while retards with the increase of ethanol amount. Structure changes during heat treatment were studied by means of DTA, XRD. TEM micrographs show that the gel particles shrink after heated at 500°C, thus the average pore size decreases. 相似文献
8.
The Bi-system tapes and coils were prepared by the powder-in-tube method. The effect of processing and heat treatment on the properties of the tapes and coils was studied. It is found that the shearing stress produced by the rolling process may destroy the 2223 phase, and the destroyed 2223 phase cannot be recovered by heat treatment, whereas the pressing stress produced by the uniaxial pressing process only makes the 2223 phase grains break, and the broken 2223 phase can be closed by the heat treatment. TheJ
c values of the rolling samples, pressing sample, and the coil with a diameter of 35 mm are over 1.3×104, 2.5×104, and 4×103 A/cm2 (77 K, 0 T), respectively. 相似文献
9.
An a posteriori (off-line) approach to the simultaneous detection and identification of quasi-periodic fragments in a numerical
sequence using their segments is analyzed. The solution of the problem is proposed for the case when the number of the desired
fragments is known. The following assumptions are made. (i) Each desired fragment of the numerical sequence coincides with
an element of the given alphabet of the reference sequences that have equal lengths (i.e., number of elements). (ii) Only
a segment (part) of the desired fragment can be processed; unprocessable parts of the fragment are interpreted as lost data.
(iii) The numbers of the elements in the sequence that correspond to the beginning of the desired fragment and the boundaries
of the segment in the fragment represent deterministic (rather than random) quantities; the boundaries of the segments are
different for different fragments; and the desired fragments are quasi-periodic in the sequence. (iv) Gaussian uncorrelated
noise impedes the observation of the sequence that contains quasi-periodic segments of the reference sequences. It is demonstrated
that the essence of the problem under study lies in the verification of a set of hypotheses on the mean value of a random
Gaussian vector (the power of this set exponentially increases with an increase in the dimension of the vector—the sequence
length). An effective a posteriori algorithm that provides for maximum-likelihood detection and identification is validated.
The estimates of the time and space complexity are related to the parameters of the problem. The results of the numerical
simulation are presented.
This work was supported by the Russian Foundation for Basic Research, project no. 03-01-00036 and 06-01-00058.
Aleksandr V. Kel’manov. Born April 25, 1952. Graduated from Izhevsk State Technical University in 1974. Received candidate’s degree in 1980 and
doctoral degree in 1994. Leading researcher of the Sobolev Institute of Mathematics, Siberian Division, Russian Academy of
Sciences. Scientific interests: mathematical methods for pattern recognition; discrete optimization; effective algorithms
for the analysis and recognition of random sequences; algorithms for the solution of applied problems; and methods and algorithms
for the processing, recognition, and synthesis of voice signals. Author of more than 120 papers.
Sergei A. Khamidullin. Born March 28, 1952. Graduated from Novosibirsk State University in 1974. Received candidate’s degree in 1997. Senior researcher
of the Sobolev Institute of Mathematics, Siberian Division, Russian Academy of Sciences. Scientific interests: mathematical
methods for pattern recognition; discrete optimization; effective algorithms for the analysis and recognition of random sequences;
algorithms for the solution of applied problems; and methods and algorithms for the processing, recognition, and synthesis
of voice signals. Author of more than 80 papers. 相似文献
10.
V. D. Belik R. V. Litvin M. S. Koval’chenko 《Powder Metallurgy and Metal Ceramics》2006,45(11-12):593-598
The influence exerted by electric-spark spraying on the kinetics of mass transfer and the physicomechanical properties of coatings is investigated. It is shown that electric-spark spraying is determined by the dynamic properties of the cathode jets, which depend on the electrical parameters of the spark discharge, the size of the interelectrode interval, and the physical properties of the coatings, which vary during spraying. 相似文献