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101.
Andrzej Kreft Edward Chrus̀ciel Bohdan Dziunikowski Jan Gyurcsak Stefan Kalita Andrzej Lenda Wojciech Przybylowicz Jan Woźniak 《Fuel》1984,63(9):1281-1284
A method for the simultaneous determination of calorific value Qr, ash yieldAr and total water content Wrt of soft brown coals is described. The method involves instrumental analysis of brown coal samples using neutron thermalization and gamma back-scattering techniques. Over 80 coal samples (1.1 kg) were analysed, having Qrvalues up to 15.5 MJ kg?1,Ar ranging from 3.6 to 76.1 wt% and Wrt ranging from 11.4 to 61.7 wt%. A comparison of the results from the instrumental method with those of standard laboratory analyses is given, followed by a discussion of the accuracy of the method and of possible ways for improving it. 相似文献
102.
Tomasz Czeppe Wojciech Zakulski Elbieta Bielaska 《Journal of Phase Equilibria and Diffusion》2003,24(3):249-254
A part of the Al-Mg phase diagram was studied in the range of composition between 48 and 61 at.% Al by DSC and SEM/EDS methods.
The temperature ranges of stability of the β, γ, and ɛ phases were considered. It was found that the congruent melting temperature
of the β phase was 450±1 °C. The Al content in that phase was determined to be 61±1 at.% Al at 420 °C. The upper temperature
limit of the stability of the ɛ phase was established to be 427±1 °C. The Al content changed from 54 at.% at 390 °C to 56
at.% at 420 °C. The lower temperature limit of the ɛ phase formation was not determined, as a result of a slow ɛ=β+γ reaction.
The hypothetical λ or ζ phases were not found, but it was observed that decomposition of oxides might produce extra thermal
effects. 相似文献
103.
Determination of the ash yield and the mineral matter content of brown coals by density measurements
Edward Chruściel Wit Jagusztyn Andrzej Kreft Andrzej Lenda Wojciech Przybylowicz Jan Woźniak 《Fuel》1983,62(3):389-390
A method of measuring the density of bed-moist brown coals based on their plastic properties is described and the feasibility of using the method for determination of the ash yield of the coal is evaluated. 相似文献
104.
105.
Wojciech Pietraszkiewicz Janusz Badur 《International Journal of Engineering Science》1983,21(9):1097-1115
Finite rotations in continuum mechanics are described by means of either a proper orthogonal tensor or finite rotation vectors. Some algebraic relations concerning the finite rotations are reviewed. Formulae expressing them in terms of displacements are given. Along each of the curvilinear coordinate lines the finite rotations are shown to satisfy some systems of the linear first-order differential equations. Each system of the equations is presented in four different but equivalent forms associated with an intermediate stretched basis or with an intermediate rotated basis. Integrability conditions of the system of equations provide various alternative forms of compatibility conditions in continuum mechanics. The displacement field is expressed through the stretch and rotation fields in the form of three successive line integrals. The formula describes the displacements to within a constant finite translation and a constant finite rotation. The procedure proposed here generalizes the formula derived by Cesàro (1906) within the classical linear theory of elasticity. 相似文献
106.
107.
Marta Legawiec-Jarzyna Wojciech Juszczyk Magdalena Bonarowska Zbigniew Kaszkur Leszek Kępiński Zbigniew Kowalczyk Zbigniew Karpiński 《Topics in Catalysis》2009,52(8):1037-1043
A series of Pt/Al2O3 catalysts were prepared by the impregnation method and were characterized by TEM, XRD, H2 and CO chemisorptions, and investigated in the hydrodechlorination of tetrachloromethane. Three Pt-rich, Pt–Au/Al2O3 catalysts (Pt100, Pt95Au5 and Pt90Au10) showed a similar metal particle size (~2.5–2.7 nm), so observed changes in the catalytic behavior are ascribed to alloying
effect, especially because a considerable degree of Pt–Au mixing was achieved in the bimetallic samples. It appeared that
by introducing very small amount of gold (10 at.%) to platinum, the catalytic activity is increased. It is argued that the
occurrence of this moderate synergistic effect is associated with a decreased tendency of surface chloriding when platinum
is alloyed with gold.
Zbigniew Kowalczyk—deceased. 相似文献
108.
Agnieszka Michalak Magdalena Nowosielska Wojciech K. Jóźwiak 《Topics in Catalysis》2009,52(8):1044-1050
The promotion of Fischer-Tropsch catalysts 10%Co/Al2O3, 10%Co/SiO2, 10%Co/TiO2 by 0.5% Ru and the modification of supports by 8.5 wt% ZrO2 have been studied. The following properties: catalyst specific surface area as well as reducibility and dispersion of metallic
phase were studied by different techniques: BET, TPR, and H2 chemisorption. The modification of supports by non-reducible ZrO2, results in a decrease of cobalt oxide reduction on Al2O3 and TiO2 but not on SiO2 supports. Additionally the enhancement of cobalt dispersion was found for all catalysts with ZrO2 modified supports. The impact of Ru promotion is likely due to the stabilization of applied supports, prevention or blockage
of interaction between surface Co species and support and an increase in cobalt oxide reducibility to the catalytically active
metallic cobalt phase. 相似文献
109.
Tomasz P. Maniecki Paweł Mierczynski Waldemar Maniukiewicz Katarzyna Bawolak Danuta Gebauer Wojciech K. Jozwiak 《Catalysis Letters》2009,130(3-4):481-488
The influence of silver and gold addition on the activity and physicochemical properties of supported Cu/CrAl3O6 catalysts was the aim of this work. The reduction of CrAl3O6 support shows only one reduction stage attributed to Cr (VI) species reduction originating from previously oxidized binary oxide. Supported copper catalysts reduce in one or two stages depending on copper concentration representing the reduction of copper oxide—CuO, copper oxide chemically combined with Cr(III) oxide as copper chromite—CuCr2O4 and Cr(VI) species originating from surface chromate ions CrO4 2?. Additionally, the introduction of silver into supported copper catalysts Cu/CrAl3O6 can led to the appearance of silver chromate phase. XRD investigations of support CrAl3O6 alone, supported copper and gold and silver promoted copper supported catalysts calcined at 400, 700 and 900 °C indicated the presence of highly amorphous alumina γ-Al2O3 like structure network in which some of cationic locations of aluminum were occupied by chromium atoms and small quantities of α-Cr2O3 phase. Additionally, for copper, silver–copper, and gold–copper supported catalysts the following oxide phases were distinguished: monometallic oxides CuO, Ag2O, binary oxides CuAl2O4, Ag2CrO4, CuCr2O4 and even ternary oxide CuAlCrO4. In the case of gold promoted copper supported catalysts metallic gold phase was detected. Activity tests carried out for these catalysts show that the most active was 20 wt.% Cu/CrAl3O6 catalyst. Promotion of copper catalysts by silver improves the activity in methanol synthesis, what can be assigned to silver chromate formation. The analogical gold chromate like formation was not confirmed. 相似文献
110.
Drinking water is a complex mixture that contains thousands of naturally occurring and anthropogenic contaminants. Liquid chromatography-mass spectrometry (LC-MS) methods have gained a tremendous popularity in monitoring nonvolatile, highly polar, and thermally labile components in drinking water. It is well recognized, however, that there are difficulties or limitations of LC-MS methods associated with (1) significant resources (time and effort) involved in sample preparation (preconcentration, fractionation, separation), (2) low screening capacity for target contaminants, and (3) insufficient capabilities for structural identification (elucidation) of nontarget contaminants. Consequently, LC-MS methods are mainly used for the detection of target contaminants (compounds identified in drinking water before), seldom for the structural identification of abundant nontarget pollutants (unidentified pollutants in drinking water), and almost never for the structural identification of nontarget components at a trace level. The paper presents a new method of electrospray ionization high field asymmetric waveform ion mobility spectrometry mass spectrometry (ESI-FAIMS-MS), which can detect a large number of water pollutants in a quick and convenient fashion without preconcentration, fractionation, derivatization, or column separation. Most importantly, the method provides structural identification of nontarget contaminants including species present in drinking water at a sub-parts-per-billion concentration level. The identification of previously unknown contaminants was based on mass measurements of investigated ions and their fragments in mass and tandem mass spectrometry. Elemental compositions of these ions, determined by mass measurements, were used to link dissociation patterns of investigated species with their chemical structures. Characterization of nontarget contaminants of chlorine-treated drinking water by ESI-FAIMS-MS has revealed many previously unknown disinfection byproducts. The most intriguing compound, from a group of highly polar hydroxycarboxylic acids discovered in the study, was the most abundant component of drinking water, glycolic acid. Glycolic acid (toxic to kidneys and associated with a moderate maternal toxicity) has never been considered as a drinking water contaminant, despite the fact that it is present in drinking water at a higher concentration (high ppm) than concentrations of highly polar water pollutants that had attracted most attention in the past. The process of structural elucidation of discovered pollutants, including ultratrace contaminants representing a variety of carboxylic acids, will be presented in detail. The structural identification of highly polar contaminants in drinking water presented in the paper is rarely reported in the literature. The key experimental feature of the ESI-FAIMS-MS method is FAIMS separation, which significantly improves the identification capabilities of mass spectrometry. 相似文献