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11.
The time-dependent film formation of two potential non-phosphorus supplemental wear inhibitors in the presence of secondary zinc dialkyldithiophosphate (ZnDTP) was studied by electrical contact resistance (ECR), auger, and X-ray photoelectron (XPS) spectroscopy. One weight percent of a molybdenum dithiocarbamate or an ashless dithiocarbamate was blended with a secondary ZnDTP, sufficient in quantity to yield 0.05 wt% phosphorus at blend level. A thorough surface examination by auger and XPS, coupled with the ECR results, detailed the deleterious effects that these supplemental antiwear additives had on ZnDTP antiwear film formation. Both carbamates interfered with antiwear film formation by secondary ZnDTP. It is speculated that MoDTC generated a competing molybdenum sulfide film that oxidized over time to form MoO 3 , which promotes wear in the ECR bench test based on literature insight. Ashless DTC also formed a competing antiwear film but not as good a film as from ZnDTP alone. 相似文献
12.
以龙冈的在不规则荷载作用下土体应变的累积损伤理论为基础,提出了基于累积损伤理论的土石坝地震永久变形分析方法。采用大型静力和动力三轴仪,对某土石坝筑坝材料的静动变形特性进行了试验研究,确定了筑坝材料的静力和动力应力应变关系、累积应变模型和相应的材料参数。利用该方法,分别对在日本2008年6月14日岩手宫城内陆M7.2级地震作用下该土石坝的在建坝体和竣工后坝体的地震永久变形特性进行了研究。结果表明:在建坝体的坝内沉降计算值与现场实测值基本吻合,并且通过与其它土石坝实测值的比较,说明竣工后坝体的坝顶沉降预测值在合理范围之内。 相似文献
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基于物性推算法的膜分离材料设计 总被引:2,自引:3,他引:2
针对渗透汽化或蒸汽渗透法进行有机溶剂混合物分离,首次提出基于物性推算法的膜分离材料设计方法。基于溶解-扩散机理模型,使用统计热力学和状态方程式为基础的GCLF-EOS模型进行溶解度计算,自由体积模型推算扩散系数,同时考虑填充型复合膜的基膜影响,建立膜渗透通量计算模型。溶解性、扩散性的物性推算结果,较好地再现芳香族有机溶剂在高分子材料中的溶解和扩散行为,复合膜的渗透通量计算值与实验测定结果基本一致。由于计算模型中不包含任何从实验直接回归参数,本设计法具有可预测性和普遍适用性。 相似文献
15.
FRED F. LANGE TAKASHI YAMAGUCHI BURTON I. DAVIS PETER E.D. MORGAN 《Journal of the American Ceramic Society》1988,71(6):446-448
The sinterability of Al2 O3 /ZrO2 composite powder compacts containing 2 and 10 vol% ZrO2 was compared to the sinterability of their single-phase constituents through constant-heating-rate experiments. The ZrO2 inclusion phase delayed the initiation of bulk shrinkage and the temperature of maximum strain rate by 100°C. The ZrO2 inclusion phase also significantly inhibited grain growth. These results, discussed with regard to the thermodynamics of pore disappearance, suggest that phenomena inhibiting grain growth may also inhibit densification. 相似文献
16.
以氧化铝(Al2O3)和石墨(C)为原料,采用碳热还原工艺合成铝氧碳(Al4O4C),借助于X射线衍射仪和场发射扫描电子显微镜研究了加热温度和保温时间对合成铝氧碳(Al4O4C)的影响。结果表明:提高加热温度,可加快Al2O3和C反应生成Al4O4C的反应速率;延长保温时间可增大Al2O3和C反应生成Al4O4C的反应程度。在反应初期主要为固-固反应,Al2O3和C直接接触反应生成Al4O4C和一氧化碳(CO);后期主要为气-固反应,Al2O3和CO气体反应生成Al4O4C和二氧化碳(CO2)。计算得到气-固反应的频率因子和活化能分别为338.66和264.19kJ/mol。 相似文献
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18.
ABSTRACT: Rutin, luteolin, luteolin-7-glucoside, and chlorogenic acid gradually decomposed during heating at 100°C. Even though they rapidly decomposed at 180°C, some decomposition products still had radical-scavenging activity. When rutin was heated in the presence of chlorogenic acid, decomposition of rutin was almost totally inhibited at 100°C, but was reduced at 180°C. These results suggest that the radical-scavenging activity is more stable than the content of original polyphenolic compounds in foods during cooking and processing. 相似文献
19.
The cell dimensions of pure triclinic 3CaO·SiO2 and monoclinic 3CaO·SiO2 solid solution (54CaO·16SiO2 ·Al2 O3 ·MgO) were determined and the powder diffraction patterns were indexed by the method of precise measurement of the spacings. The lattice constants are expressed in terms of triclinic or monoclinic cells corresponding to pseudo-orthorhombic cells derived from Jeffery's trigonal cell. The apparent lattice constants for pure 3CaO·SiO2 are a = 12.195 a.u., b = 7.104 au., c = 25.096 a.u., α= 90°, β= 89°44'γ= 89°44'; for 54CaO·16SiO2 .-Al2 O3 MgO, a = 12.246 a.u., b = 7.045 a.u., c = 24.985 a.u., β= 90°04'. Precise lattice constants of Jeffery's monoclinic lattice for 54CaO.-16SiO2 -Al2 O3 ·MgO are derived as a = 33.091 a.u., b = 7.045 a.u., c = 18.546 a.u., β= 94°08'. High-temperature X-ray patterns showed that pure triclinic 3CaO·SiO2 transformed to a monoclinic form at about 920°C. and then to a trigonal form at about 970°C. Monoclinic 54CaO.16SiO2 ·Al2 O3 –MgO transformed to trigonal at about 830°C. These transitions were reversible and reproducible and were accompanied by only slight deformation of the structure forms. 相似文献
20.
Whole grapefruit were exposed to 5, 15, 30, 50, and 100 krad doses of gamma-radiation. Seeds were removed and half-embryos, consisting of one cotyledon and embryo axis, dissected from the surrounding tissue. Nonirradiated half-embryos germinated faster than intact or partially dissected (outer seed coat removed) seeds. Shoot elongation was also quicker, occurring within 6 days. Irradiated half-embryos over 15 krad doses showed markedly reduced root growth and shoot elongation was almost totally retarded. Differences between irradiated and nonirradiated half-embryo were not affected when variety, harvest date, and fruit storage conditions were varied. This test could thus discriminate between irradiated and non irradiated grapefruit. 相似文献