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91.
92.
NiFe (Oxy) Hydroxides Derived from NiFe Disulfides as an Efficient Oxygen Evolution Catalyst for Rechargeable Zn–Air Batteries: The Effect of Surface S Residues 下载免费PDF全文
Tanyuan Wang Gyutae Nam Yue Jin Xingyu Wang Pengju Ren Min Gyu Kim Jiashun Liang Xiaodong Wen Haeseong Jang Jiantao Han Yunhui Huang Qing Li Jaephil Cho 《Advanced materials (Deerfield Beach, Fla.)》2018,30(27)
A facile H2O2 oxidation treatment to tune the properties of metal disulfides for oxygen evolution reaction (OER) activity enhancement is introduced. With this method, the degree of oxidation can be readily controlled and the effect of surface S residues in the resulted metal (oxy)hydroxides for the OER is revealed for the first time. The developed NiFe (oxy)hydroxide catalyst with residual S demonstrates an extraordinarily low OER overpotential of 190 mV at the current density of 10 mA cm?2 after coupling with carbon nanotubes, and outstanding performance in Zn–air battery tests. Theoretical calculation suggests that the surface S residues can significantly reduce the adsorption free energy difference between O* and OH* intermediates on the Fe sites, which should account for the high OER activity of NiFe (oxy)hydroxide catalysts. This work provides significant insight regarding the effect of surface heteroatom residues in OER electrocatalysis and offers a new strategy to design high‐performance and cost‐efficient OER catalysts. 相似文献
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94.
The aim of this research was to examine the effect of microstructural parameters on the tensile properties of dif- ferent compositions of tungsten heavy alloys. The microstructural parameters (grain size, connectivity, contiguity, and solid volume fraction) were measured and were found to have a significant effect on the tensile properties of tungsten-based heavy alloys. The microstructural parameters of W-Ni-Fe alloys are sufficiently different to present a range of me- chanical properties. It is concluded that the mechanical properties of tungsten heavy alloys largely depend on the micro- structural parameters and their ductility is particularly harmed when grains are contiguous. 相似文献
95.
Bismuth selenide thin films were grown on Pt substrate via the route of electrochemical atomic layer epitaxy (ECALE) in this work for the first time. The electrochemical behaviors of Bi and Se on bare Pt, Se on Bi-covered Pt, and Bi on Se-covered Pt were studied by cyclic voltammetry and coulometry. A steady deposition of Bi2Se3 could be attained after negatively stepped adjusting of underpotential deposition (UPD) potentials of Bi and Se on Pt in the first 40 deposition cycles. X-ray diffraction (XRD) analysis indicated that the films were single phase Bi2Se3 compound with orthorhombic structure, and the 2:3 stoichiometric ratio of Bi to Se was verified by EDX quantitative analysis. The optical band gap of the as-deposited Bi2Se3 film was determined as 0.35 eV by Fourier transform infrared spectroscopy (FTIR), which is consistent with that of bulk Bi2Se3 compound. 相似文献
96.
《Journal of the European Ceramic Society》2004,24(6):1069-1072
The present paper contains an experimental study of two different kinds of PZT suspensions for direct ink jet printing at 25 and 120 °C, respectively. The effect of processing parameters such as mixing time, the amount of dispersant, solid loading and milling method was investigated for the optimisation of viscosity for feasible jetting. The viscosity of PZT suspensions was within 5–15 mPa·s range for room temperature suspensions with MEK/EtOH medium and 10–20 mPa·s for high temperature suspensions with wax medium. FTIR analysis is also presented to explain the rheological behaviour of PZT suspensions. Finally, a demonstration of room temperature jetting of PZT suspension is shown. 相似文献
97.
《International Journal of Hydrogen Energy》2019,44(54):28947-28957
In this work, we investigated the performance and stability of a large flat-tube SOFC with symmetric double-sided cathodes (DSC), which was directly fueled with methane. The effect of steam/carbon (S/C) ratio, temperature, and current density on the performance, and long-term stability of the DSC as well as the catalytic behavior of the anode was investigated in details. The thick anode support and inner channels of the DSC formed an efficient microreactor for steam-reforming of methane, resulting in high conversion rate of methane and CO selectivity. In particular, when the S/C was 2, the conversion of CH4 at 750 °C achieved 100% in the DSC and no carbon deposition was observed. Moreover, the voltage of DSC with was stable throughout 190 h under a discharge current density of 0.257 A cm−2. 相似文献
98.
《Calphad》2003,27(2):201-211
Based on fundamental thermodynamics and a simple energy model for solid M2O3 oxides, two atomic parameters of their constituent elements are identified that govern the solid phase stability in an M2O3–M2′O3 binary system. They are P1=|rA−rB| and P2=(rA+rO)(rB+rO)(rA+rB+2rO), where, rA, rB and rO are the ionic radii of ion A, ion B and oxygen, respectively. Using 237 known M2O3–M2′O3 systems and these two parameters (P1 and P2), new rules were obtained not only on the formability of stable complex oxides but also on the conditions that these compounds being of MM′O3 stoichiometry and further of ABO3-type perovskite structure. The classification accuracy of such rules reaches respectively 98.7% for formability of complex oxides, 97.9% for the MM′O3 stoichiometry test, and 100% for the ABO3-type perovskite structure prediction. Thirty seven new systems are used to validate these empirical rules, and the prediction is in good agreement with experiment. The influence of ionic size difference on the phase stability is further discussed based on the proposed energy model. The new rules may help material scientists to practically predict new complex compounds as well as to further theoretically study phase stability in M2O3–M2′O3 systems. 相似文献
99.
《Scripta materialia》2002,46(2):121-126
TiCx and Cu–TiCx have been formed by self-propagating high-temperature synthesis (SHS) from elemental powder mixtures with a range of C/Ti ratios. When no copper was present, the carbide stoichiometry closely followed that of the starting powders. In the presence of copper, formation of copper–titanium intermetallics and solid solutions resulted in a different carbide stoichiometry. 相似文献
100.