全文获取类型
收费全文 | 8212篇 |
免费 | 580篇 |
国内免费 | 259篇 |
专业分类
电工技术 | 258篇 |
综合类 | 595篇 |
化学工业 | 1726篇 |
金属工艺 | 532篇 |
机械仪表 | 363篇 |
建筑科学 | 750篇 |
矿业工程 | 236篇 |
能源动力 | 293篇 |
轻工业 | 1507篇 |
水利工程 | 150篇 |
石油天然气 | 335篇 |
武器工业 | 37篇 |
无线电 | 281篇 |
一般工业技术 | 496篇 |
冶金工业 | 599篇 |
原子能技术 | 82篇 |
自动化技术 | 811篇 |
出版年
2024年 | 17篇 |
2023年 | 81篇 |
2022年 | 149篇 |
2021年 | 180篇 |
2020年 | 204篇 |
2019年 | 199篇 |
2018年 | 188篇 |
2017年 | 240篇 |
2016年 | 250篇 |
2015年 | 239篇 |
2014年 | 400篇 |
2013年 | 520篇 |
2012年 | 533篇 |
2011年 | 620篇 |
2010年 | 460篇 |
2009年 | 513篇 |
2008年 | 440篇 |
2007年 | 570篇 |
2006年 | 506篇 |
2005年 | 526篇 |
2004年 | 409篇 |
2003年 | 372篇 |
2002年 | 255篇 |
2001年 | 245篇 |
2000年 | 182篇 |
1999年 | 135篇 |
1998年 | 88篇 |
1997年 | 93篇 |
1996年 | 67篇 |
1995年 | 71篇 |
1994年 | 51篇 |
1993年 | 53篇 |
1992年 | 41篇 |
1991年 | 22篇 |
1990年 | 18篇 |
1989年 | 7篇 |
1988年 | 21篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1975年 | 3篇 |
1966年 | 4篇 |
1962年 | 2篇 |
1957年 | 2篇 |
排序方式: 共有9051条查询结果,搜索用时 15 毫秒
31.
Wenlu Song Rui Huang Hao Guo Chunguang Yin Chuanling Wang Jun Cheng Weijuan Yang 《中国化学工程学报》2021,37(9):114-120
Steam pretreatment was employed to disrupt microalgal cells for lipids extraction.Effects of steam pre-treatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM) and transmission electron microscopy (TEM).Effect of treatment on lipid extraction was also stud-ied.Microalgal cell walls were distorted after steam pretreatment due to the hydrolysis of organic macro-molecules contained in cell wall.Maximum curvature was increased from 1.88 × 10-6 m-1 to 1.43 × 10-7 m-1 after treatment with the steam at 130 ℃.The fractal dimension of microalgal cells increased from 1.25 to 1.30 after pretreatment for 15 min,and further increased to 1.47 when the pre-treatment time was increased to 60 min.Increased steam pretreatment temperature and time enhanced the hydrolysis of organic macromolecules,and finally destroyed microalgal cell walls at pretreatment temperature of 130 ℃ and pretreatment time of 60 min.Lipid extracted from wet microalgal was signif-icantly increased (2.1-fold) after pretreatment. 相似文献
32.
33.
V.V. Pani? V.M. Jovanovi? M.W. Barsoum A.B. Dekanski 《Surface & coatings technology》2007,202(2):319-324
Electroactive oxide coatings on titanium, known in industrial chlorine production as dimensionally stable anodes (DSA), are of limited service life owing to the dissolution of active oxide, but also due to low corrosion stability of titanium, at high anodic potentials and elevated temperatures. In order to improve the anode stability, ternary carbide, Ti3SiC2, could be a promising material for the coating support, since chemical corrosion stability of Ti3SiC2 is significantly higher if compared to Ti. In this work, the possibility of the sol-gel preparation of RuO2-TiO2 coating on Ti3SiC2 is investigated and comparison of the basic characteristics of sol-gel processed oxide coating, Ru0.5Ti0.5O2, applied onto Ti3SiC2 and Ti, is reported. Microscopic investigation of the coating surface showed that considerably less cracked coating is formed onto the Ti3SiC2 support. Slightly higher voltammetric currents are registered for Ti3SiC2-supported coating in H2SO4 and NaCl solution. The activity for chlorine evolution is higher, while the currents of oxygen evolution reaction are lower for Ru0.5Ti0.5O2/Ti3SiC2 anode in comparison to Ru0.5Ti0.5O2/Ti anode. Even though these preliminary results on the basic electrochemical properties of Ru0.5Ti0.5O2/Ti3SiC2 anode and chemical stability of Ti3SiC2 are promising, the accelerated stability test in NaCl solution showed that coated Ti3SiC2 is not anodically stable and lasts considerably shorter than Ru0.5Ti0.5O2/Ti anode prepared and tested under the same conditions. 相似文献
34.
X.F. Liu 《Corrosion Science》2007,49(9):3494-3513
In the study, on the basis of material analysis of 6016 aluminum alloy widely used in Europe automotive industry, the influences of surface pretreatment on filiform corrosion and adhesion of epoxy coating/aluminum alloy interface were investigated, and the effect of rolling direction and coating property on filiform corrosion was also examined. The alloy surfaces were pretreated with etching solution, and then, respectively, with Aminopropyl silane solution, Aminopropyl phosphonate solution, and hexamethyldisiloxane plasma.The results showed that the susceptibility of pretreated surface to filiform corrosion was basically consistent with the distribution of intermetallic particles, and that water permeation and the tensility of coating were necessary for filament to grow. HMDSO plasma pretreatment could not only efficiently cover the matrix of 6016 aluminum alloy and cathodic intermetallic particles containing Al, Si, Mn, and Fe, but also apparently promote the adhesion of epoxy coating/aluminum alloy, as a result, the specimens with plasma pretreatment exhibited the superior performance in the filiform corrosion and peeling tests, so it was suitable to apply for the pretreatment of aluminum alloy in automotive industry. 相似文献
35.
36.
37.
D-HPG废水的预处理 总被引:1,自引:0,他引:1
D-对羟基苯甘氨酸制药废水 COD高 ,成分复杂。采用 Fe粉及 Fenton试剂预处理 ,COD总去除率高达98%以上。小试确定了 Fe粉加入量为 14 0 g/ L、曝气时间为 7h、Fenton法预处理 D- HPG废水的最佳反应条件 :H2 O2 质量浓度为 2 1.5 g/ L,Fe SO4 质量浓度为 3.8g/ L,氧化时间为 4 h,p H为 5 相似文献
38.
39.
40.
Using TiO2 as carrier, CuO/TiO2 catalysts with different CuO loading were prepared by the impregnation method. The catalytic activities in NO+CO reaction
were examined with a micro-reactor gas chromatography reaction system and the methods of TPR, XPS and NO-TPD. It was found
that the catalytic activities were affected by pretreatment atmosphere, i.e. H2 atmosphere > reduction–reoxidation > 10%CO/He > reaction gas (fresh sample). NO decomposition was better by low-valence Cu
species than by high-valence Cu species, i.e. Cu0>Cu+>Cu2+. The XPS results indicated that Cu species on CuO/TiO2 were Cu0, Cu+, normal Cu2+(Cu2+(I)) and chain-structured Cu2+(Cu2+(II)) as –Cu–O–Ti–O–. The activities of Cu2+(II) were much higher than that of Cu2+(I), but both species were very unstable in the reaction atmosphere and easily reduced by CO, which accounted for the variable
activities of fresh catalysts with increasing reaction temperature. In NO+CO reaction, the redox process was a cycle of Cu+–Cu2+(I) at low reaction temperature but was a cycle of Cu0–Cu+ at high reaction temperature. As shown by NO-TPD, high catalytic activities could be attributed to the following factors,
e.g. oxygen caves on the catalyst’s surface after pretreatment with H2 and reduction–reoxidation, formation of Cu0 after pretreatment with H2, and increment of Cu species dispersion and formation of Cu2+(II) after pretreatment with reduction–reoxidation. 相似文献