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1.
Corncob liquefaction in supercritical ethanol–water was performed with and without the addition of an alkali catalyst by direct addition or biomass impregnation in a 250-cm3 batch reactor. The effects of temperature, solvent and alkali addition on the biomass conversion level and oil yield were investigated to find the optimum condition. For non-catalytic liquefaction using a 1:1 (v/v) ethanol: water ratio, a maximum oil yield and conversion level of 49.0% and 93.4%, respectively, were obtained at 340 °C. For alkali catalytic liquefaction, the oil yield with KOH addition (57.5%) was higher than that from KOH-impregnated corncob liquefaction (43.3%). The oil from liquefaction with KOH addition had higher heating value (26.7–35.3 MJ kg−1) than the corncob (19.1 MJ kg−1). The dominant components of the obtained oil were found by GC/MS analysis to be aldehyde, ester, phenol derivatives and aromatic compounds. 相似文献
2.
Yingchao Hu Wenqiang Liu Yuandong Yang Xianliang Tong Qianjun Chen Zijian Zhou 《Ceramics International》2018,44(14):16668-16677
Li4SiO4 sorbents for high-temperature CO2 removal have drawn extensive attention owing to their potential application in carbon capture and storage (CCS). The major challenge in the application lies in the poor CO2 capture performance under realistic conditions of low CO2 concentrations, owing to the dense structure and poor porosity. In this work, Li4SiO4 sorbents were prepared with porous micromorphologies and large contact areas using a variety of organometallic Li-precursors, achieving fast CO2 sorption kinetics, high capacity and excellent cyclic stability at a low CO2 concentration (15?vol%). It was found that a high conversion of ~?74% was maintained for pure Li4SiO4 even after 100 sorption/desorption cycles. Moreover, by doping with Na2CO3 to reduce the CO2 diffusion resistance, the conversion of the sorbent was further enhanced to 93.2%. The enhancement mechanism of alkali carbonate have been proven here to be ascribed to the formation of the eutectic melt of Li/Na carbonates, the existence and function of which has been confirmed in this study. 相似文献
3.
燕皮传统加工工艺中碱液对肉糜特性的影响 总被引:1,自引:1,他引:0
燕皮是以猪肉和甘薯粉为原料,手工制成的薄如纸且经煮不烂的传统食品。在传统制作燕皮过程中添加山榉灰配制的碱液是影响肉糜品质的关键步骤。通过测定制作燕皮过程中各工序样品的氮溶解指数、持水性、乳化稳定性、pH值和粘度,利用SDS-PAGE分析样品中的蛋白质组分、利用光学显微镜观察它们的结构变化,证实植物碱液能够提高样品的氮溶解指数、持水性和乳化稳定性并且延迟了肉糜硬化。同时实验证明碳酸碱(Na2CO3或K2CO3)可替代传统工艺中的植物碱,为后续标准化、工业化生产提供可行条件。 相似文献
4.
Initial stages of surface erosion have been studied for NaCl and LiF single crystals bombarded by Ar+ ions with 20 keV. For irradiation with doses D=1010-1011 ions/cm2, exoelectron emission has been used, whereas for higher doses, we have used electron microscopy. Two stages of initial surface erosion have been identified; for small doses, there is slow development of atomic-scale roughening, which reaches its peak when areas damaged by closest incident ions start to overlap, and then, beginning with D=1016 ions/cm2, there is rapid etching, deep into the crystal, followed by the emergence of secondary microscopic structure, i.e. caverns, concentric closed steps and terraces. Ion-induced surface structure of alkali halide crystals has been shown to depend strongly on the presence of foreign particles on the surface, as well as on segregation. Topography of thin carbon films and some metals have been discussed. 相似文献
5.
Two commercial SCR catalysts, with a nominal W content of about 9 wt.% and a V nominal content of 0.55 and 1.8 wt.%, respectively, were contacted with different amounts of Na and K and with HCl vapours in order to simulate poisoning by species more specifically contained in exhaust gases from MSW combustion. Catalysts were characterised using XRD analysis, SEM/EDX analysis, BET and pore size distribution measurements, NH3 TPD, TG analysis. Poisoning agents do not cause loss of surface area nor pore occlusion. A significant loss of surface acidity was observed upon alkali metals poisoning whereas a decreasing of vanadium content was observed for the more concentrated catalysts upon HCl poisoning. Catalysts deactivation is proportional to the number of acid sites neutralised by alkali metals adsorbing ammonia in the temperature range typical of SCR process. HCl promotes the formation of new acid sites showing a lower activity compared to the original one. 相似文献
6.
将高炉用SiAlON结合刚玉砖制成外部尺寸为50mm×50mm,内孔尺寸为25mm×25mm的坩埚,分别加入由Na2CO3、K2CO3、ZnO和宝钢高炉现场高炉灰配制的炉渣(其w(Na2O+K2O)=2.75%,w(ZnO)=5.1%)和用K2CO3、ZnO、石墨配制的炉渣(其w(Na2O+K2O)=25%,w(ZnO)=25%),然后分别在还原气氛下于1350℃16h和1100℃40h进行侵蚀试验。将侵蚀后的试样纵向对称剖开,观察渣对试样的侵蚀和渗透情况,进行SEM和EDAX分析。结果表明:碱金属和锌含量不同的两种炉渣对SiAlON结合刚玉砖的侵蚀速度都很小;碱金属侵蚀机理主要是SiAlON与碱蒸气反应生成钾霞石,与渣反应生成铁橄榄石,并参与硅酸盐玻璃相的生成;刚玉颗粒与渣中的FeO、Na2O和K2O反应生成铁铝尖晶石和少量针状β-Al2O3;锌对该砖没有产生明显的化学侵蚀。 相似文献
7.
Baishen Liang Alessandro Gomez Jose L. Castillo Daniel E. Rosner 《Chemical Engineering Communications》1989,85(1):113-133
In carrying out partial vapor condensations using actively cooled surfaces it is known that 'mist' formation can occur within thermal boundary layers (Rosner and Epstein, 1968), dramatically modifying total deposition fluxes. Using a combination of flash-evaporation (Rosner and Liang, 1986) and laser probing techniques, we report new experimental results on binary alkali salt (K2SO4 + Na2SO4) deposition from combustion gases showing that the deposition rate of potassium sulfate first increases with the addition of sodium sulfate until the concentration of Na2SO4 reaches a (target surface temperature dependent) 'threshold' value. Further increases in the concentration of Na2SO4 dramatically decrease the total deposition rate of K2SO4, implying that potassium sulfate-containing microdroplets are formed within the thermal boundary layer, which, despite their thermophoretic drift toward the target, are not collected as effectively as the 'parent' K2SO4-vapor species. Laser light scattering measurements clearly reveal that suspended particles exist near the deposition surface under these conditions. Our experimental results on mass transfer rate and light scattering are consistent with those predicted using laminar boundary layer theory (Castillo and Rosner, 1989b) coupling both binary salt vapor deposition with particle vapor scavenging and deposition. Comparisons of our observed mist onset conditions (implying critical supersaturations near unity) with those expected using homogeneous nucleation theory suggest that the binary alkali sulfate mist nucleation mechanism is, instead, heterogeneous, even in our relatively 'clean' combustion products. Because of the; well-known vapor pressure reduction phenomenon associated here with the formation of non-ideal solutions, binary systems are shown to provide convenient 'vehicles' to investigate BL mist formation onset conditions and CVD-rate consequences without requiring the more extreme surface coolings characteristic of unary condensible vapor systems. An understanding of this dramatic phenomenon, obtained via such laboratory experiments and calculations, will allow its inclusion in future deposition rate calculations of engineering importance. 相似文献
8.
通过对发生腐蚀穿孔的BA-1104裂解炉对流段二次注汽过热炉管进行了宏观腐蚀形貌分析,对含裂纹部位进行了光学显微镜观察,断口进行扫描电镜观察以及对腐蚀产物的化学成分和金相组织分析,指出造成炉管腐蚀穿孔的决定性因素与操作温度及介质中存在的碱有关。进而提出了腐蚀控制与防范的措施,确保裂解炉的安全运行。 相似文献
9.
G. Neri G. Rizzo S. Galvagno A. Donato M. G. Musolino R. Pietropaolo 《Applied catalysis. B, Environmental》2003,42(4):381-391
Alkali-doped FeV oxide catalysts supported on -alumina were prepared and their catalytic activity in the combustion of diesel soot is reported. The catalysts were characterized by XRD, TPR and SEM–EDX analysis. The influence of the nature of the alkali metal (K and Cs), the temperature of treatment of the catalysts and the stability to sulfur poisoning have been investigated.
Catalysts doped with Cs were the most active and stable also after several combustion cycles and in the presence of sulfur in the stream. The activity measurements and microstructural results suggest that the combustion of soot is favored on catalysts where amorphous phases and/or mixed Fe---V---O phases, ensuring an intimate contact between iron and vanadium, are present. A reaction mechanism involving the participation of the redox couple Fe(II)–Fe(III) in the activation of the vanadium combustion sites, is proposed. 相似文献
10.