全文获取类型
收费全文 | 2765篇 |
免费 | 390篇 |
国内免费 | 137篇 |
专业分类
电工技术 | 19篇 |
技术理论 | 1篇 |
综合类 | 240篇 |
化学工业 | 1334篇 |
金属工艺 | 148篇 |
机械仪表 | 15篇 |
建筑科学 | 87篇 |
矿业工程 | 37篇 |
能源动力 | 91篇 |
轻工业 | 81篇 |
水利工程 | 11篇 |
石油天然气 | 71篇 |
武器工业 | 5篇 |
无线电 | 201篇 |
一般工业技术 | 867篇 |
冶金工业 | 75篇 |
原子能技术 | 2篇 |
自动化技术 | 7篇 |
出版年
2024年 | 4篇 |
2023年 | 119篇 |
2022年 | 96篇 |
2021年 | 148篇 |
2020年 | 172篇 |
2019年 | 145篇 |
2018年 | 125篇 |
2017年 | 130篇 |
2016年 | 140篇 |
2015年 | 131篇 |
2014年 | 135篇 |
2013年 | 139篇 |
2012年 | 209篇 |
2011年 | 249篇 |
2010年 | 156篇 |
2009年 | 170篇 |
2008年 | 135篇 |
2007年 | 215篇 |
2006年 | 176篇 |
2005年 | 176篇 |
2004年 | 116篇 |
2003年 | 66篇 |
2002年 | 53篇 |
2001年 | 31篇 |
2000年 | 23篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有3292条查询结果,搜索用时 15 毫秒
1.
《Ceramics International》2021,47(22):31073-31083
Pluronic 31R1 surfactant and MCM-41 silica were used to fabricate mesoporous Ag2O/g-C3N4 heterostructures with improved surface areas. The fabricated mesoporous nanocomposite was used to photo oxidize ciprofloxacin. The TEM images of Ag2O/g-C3N4 indicated a uniform dispersion of spherical approximately 4-nm Ag2O nanoparticles on g-C3N4. The mesoporous 0.9% Ag2O@g-C3N4 heterostructure exhibited 100% efficiency in ciprofloxacin oxidation within 60 min when compared with the 25% efficiency in 120 min of pure mesoporous Ag2O and 10% efficiency in 120 min of pure g-C3N4. The highest ciprofloxacin oxidation efficiency achieved was 100%, which was four and ten times better than those of Ag2O and g-C3N4, respectively. This superior performance of the mesoporous Ag2O/g-C3N4 was attributed to the high dispersion of nano-sized mesoporous Ag2O particles on the g-C3N4 surface, narrow bandgap, and significantly high surface areas. The powerful interaction between Ag2O and g-C3N4 ensured robust durability of Ag2O/g-C3N4 heterostructures, which is evident in the fact that five recycling trials of the photocatalyst rendered a minimal loss of efficiency. 相似文献
2.
Improved photocatalytic hydrogen production from methanol/water solution using CuO supported on fluorinated TiO2 下载免费PDF全文
3.
4.
Neodymium-doped ZnO nanorods (Nd/ZNRs) were prepared for the first time by a simple and surfactant-free solvothermal route. The synthesized samples were characterized using different instrumental techniques. The photoluminescence results showed that the Nd(2.0 at%)/ZNRs exhibited the highest separation rate of charge carriers and the highest formation rate of hydroxyl radicals. The photocatalytic activities of synthesized samples were investigated toward the degradation of endocrine disrupting chemical resorcinol under natural sunlight irradiation. Among the samples, Nd(2.0 at%)/ZNRs showed considerable improvement in the photocatalytic activity for the resorcinol degradation as compared to ZNRs and commercial TiO2. Kinetic studies revealed that the photocatalytic degradation of resorcinol obeyed pseudo-first-order kinetic. The high-performance liquid chromatography and total organic carbon analyses also demonstrated the progressive mineralization of resorcinol into carbon dioxide and water. Furthermore, high stability of Nd/ZNRs in photocatalytic reaction also demonstrated promising potential toward practical applications in purifying environmental pollutants. 相似文献
5.
为研究碱改性前后复合纳米纤维膜的光催化降解性能,首先利用静电纺丝技术制备聚丙烯腈/醋酸纤维素/二氧化钛(PAN/CA/TiO2)复合纳米纤维膜,依次用0.05、0.10 mol/L的氢氧化钠溶液对其进行碱处理,制得聚丙烯腈/再生纤维素/二氧化钛(PAN/RC/TiO2)复合纳米纤维膜,并应用于染料废水处理。借助扫描电子显微镜、傅里叶红外光谱仪及接触角测量仪等手段表征了复合纳米纤维膜的结构与亲水性;同时研究了复合纳米纤维膜的力学与光催化降解性能。结果表明:经碱处理后,复合纳米纤维膜的静态接触角由125.30°减小到10.20°,亲水性能得到很大的改善;PAN/RC/TiO2复合纳米纤维膜对亚甲基蓝(MB)溶液的降解率达到91.2%,而空白对照样对MB溶液的降解率仅为10.1%,且重复使用3次后,复合纳米纤维膜对MB溶液的降解率仍达74.7%。 相似文献
7.
以乙二醇为溶剂,KAc为助剂,采用溶剂热法合成多级ZnO微球。通过改变反应温度来调控ZnO微球形貌,并对合成的ZnO微球进行XRD、SEM、PL和UV-Vis DRS等表征分析。结果表明,合成的ZnO为六方纤锌矿晶体结构,由短纳米棒自组装成多级微球。在紫外-可见光照射下,ZnO表现出优异的光催化降解苯酚活性,180℃合成的ZnO样品光催化活性明显优于其他温度合成的样品。用0.1 g的ZnO降解100 mL浓度为5 mg·L~(-1)的苯酚溶液,光照150 min降解率达94.5%。多级ZnO微球光催化性能的提高可推测为较窄的禁带宽度(3.08 eV)有利于吸收光子,较小的晶粒尺寸(25.38 nm)、粗糙的表面以及中空结构有利于反应液与催化剂表面的充分接触。此外,由捕获实验证实光催化降解苯酚的机理是羟基(·OH)为主要的活性自由基,在苯酚降解过程中起主要作用。 相似文献
8.
《Ceramics International》2021,47(22):31302-31310
Control of Nitrogen dioxide (NO2) byproducts is of great importance for the photocatalytic NO removal and environmental remedy. However, individual semiconductor photocatalysts generally show limited capabilities for selective NO removal due to severe charge recombination and inadequate redox potentials. Herein, the cotton-like g-C3N4 was modified with Ti3C2@TiO2 to construct a heterojunction photocatalyst Ti3C2@TiO2/g-C3N4, which showed outperformed photocatalytic NO removal and MB degradation abilities compared to the individual photocatalysts under visible light irradiation. The UV–vis absorption spectra and photoluminescence (PL) spectra confirmed that Ti3C2@TiO2/g-C3N4 photocatalyst was endowed with superior light utilization and separation/transfer ability of charge carriers due to the presence of n-n heterojunction and Schottky barrier. Furthermore, the g-C3N4, Ti3C2, and TiO2 were closely contacted showing a high specific surface area, which promoted the charge transfer and the exposure of more active sites, further inducing the formation of more active species. Therefore, the designed photocatalyst delivered a high removal rate of NO and a suppressed discharge of NO2. Notably, the photocatalyst Ti3C2@TiO2/g-C3N4 also presented superior NO removal ability during the cycling experiment, indicating their outstanding stability and recyclability. Besides, the effects of active species were monitored using a trapping experiment to propose probable photocatalytic mechanism. This study could shed a new light to the design of photocatalyst for air purification in the future. 相似文献
9.
Wei Shao Qianqian Pan Qiaoli Chen Chongzhi Zhu Weijian Tao Haiming Zhu Huijun Song Xuelu Liu Ping-Heng Tan Guan Sheng Tulai Sun Xiaonian Li Yihan Zhu 《Advanced functional materials》2021,31(3):2006738
Metallic nanocrystals manifest themselves as fascinating light absorbers for applications in plasmon-enhanced photocatalysis and solar energy harvesting. The essential challenges lie in harvesting the full-spectrum solar light and harnessing the plasmon-induced hot carriers at the metal–acceptor interface. To this end, a cooperative overpotential and underpotential deposition strategy is proposed to mitigate both the challenges. Specifically, by utilizing both ionic additive and thiol passivator to introduce symmetry-breaking growth over gold icosahedral nanocrystals, the microscopic origin can be attributed to the site-specific nucleation of stacking faults and dislocations. By adopting asymmetric crystal shape and unique surface facets, such nanocrystals attain high activity toward photocatalytic ammonia borane hydrolysis, arising from combined broadband plasmonic properties and enhanced direct transfer of hot electrons across the metal–adsorbate interface. 相似文献
10.
采用分子组装的方法,以硅藻土为基底制备TiO_2/硅藻土、TiO_2/FeOOH/硅藻土纳米复合材料,通过UV-Vis、TEM方法对材料进行表征,以甲基橙溶液为目标降解物探究纳米复合材料的光催化性能,结果表明,基底制备TiO_2/硅藻土、TiO_2/FeOOH/硅藻土纳米复合材料对甲基橙均有不错的降解率,其中TiO_2/FeOOH/硅藻土纳米复合材料降解率达到67.16%。 相似文献