全文获取类型
收费全文 | 2211篇 |
免费 | 125篇 |
国内免费 | 124篇 |
专业分类
电工技术 | 36篇 |
综合类 | 114篇 |
化学工业 | 829篇 |
金属工艺 | 614篇 |
机械仪表 | 37篇 |
建筑科学 | 8篇 |
矿业工程 | 43篇 |
能源动力 | 93篇 |
轻工业 | 4篇 |
水利工程 | 3篇 |
石油天然气 | 4篇 |
武器工业 | 7篇 |
无线电 | 104篇 |
一般工业技术 | 422篇 |
冶金工业 | 116篇 |
原子能技术 | 18篇 |
自动化技术 | 8篇 |
出版年
2024年 | 6篇 |
2023年 | 38篇 |
2022年 | 44篇 |
2021年 | 57篇 |
2020年 | 68篇 |
2019年 | 64篇 |
2018年 | 60篇 |
2017年 | 92篇 |
2016年 | 78篇 |
2015年 | 53篇 |
2014年 | 72篇 |
2013年 | 130篇 |
2012年 | 120篇 |
2011年 | 164篇 |
2010年 | 133篇 |
2009年 | 146篇 |
2008年 | 123篇 |
2007年 | 160篇 |
2006年 | 170篇 |
2005年 | 133篇 |
2004年 | 137篇 |
2003年 | 84篇 |
2002年 | 64篇 |
2001年 | 49篇 |
2000年 | 40篇 |
1999年 | 39篇 |
1998年 | 35篇 |
1997年 | 28篇 |
1996年 | 17篇 |
1995年 | 15篇 |
1994年 | 13篇 |
1993年 | 10篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1974年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有2460条查询结果,搜索用时 31 毫秒
1.
2.
《中国有色金属学会会刊》2021,31(12):3800-3813
The Fe−Ni−TiO2 nanocomposite coatings were electrodeposited by pulse frequency variation. The results showed that the nanocomposite with a very dense coating surface and a nanocrystalline structure was produced at higher frequencies. By increasing the pulse frequency from 10 to 500 Hz, the iron and TiO2 nanoparticles contentswere increased in expense of nickel content. XRD patterns showed that by increasing the frequency to 500 Hz, an enhancement ofBCC phase was observed and the grain size of deposits was reduced to 35 nm. The microhardness and the surface roughness were increased to 647 HV and 125 nm at 500 Hz due to the grain size reduction and higher incorporation of TiO2 nanoparticles into the Fe−Ni matrix (5.13 wt.%). Moreover, the friction coefficient and wear rate values were decreased by increasing the pulse frequency;while the saturation magnetization and coercivity values of the composite deposits were increased. 相似文献
3.
Miroslava Horynová Michaela Remešová Lenka Klakurková Karel Dvořák Ivana Ročňáková Shaokun Yan Ladislav Čelko Guang-Ling Song 《Journal of the American Ceramic Society》2019,102(1):123-135
Magnesium, as a biodegradable metal, offers great potential for use as a temporary implant material, which dissolves in the course of bone tissue healing. It can sufficiently support the bone and promote the bone healing process. However, the corrosion resistance of magnesium implants must be enhanced before its application in clinical practice. A promising approach of enhancing the corrosion resistance is deposition of bioactive coating, which can reduce the corrosion rate of the implants and promote bone healing. Therefore, a well-designed substrate-coating system allowing a good control of the degradation behavior is highly desirable for tailored implants for specific groups of patients with particular needs. In this contribution, the influence of coating formation conditions on the characteristics of potentiostatically electrodeposited CaP coatings on magnesium substrate was evaluated. Results showed that potential variation led to formation of coatings with the same chemical composition, but very different morphologies. Parameters that mostly influence the coating performance, such as the thickness, uniformity, deposits size, and orientation, varied from produced coating to coating. These characteristics of CaP coatings on magnesium were controlled by coating formation potential, and it was demonstrated that the electrodeposition could be a promising coating technique for production of tailored magnesium-CaP implants. 相似文献
4.
5.
6.
Ying Gao Weihuang Zhu Yaqi Li Junli Li Sining Yun Tinglin Huang 《International Journal of Hydrogen Energy》2021,46(15):9707-9717
A novelty two-step synthesized porous carbon felt (PCF) cathode modified by cyclic voltammetric (CV) electrodeposited polypyrrole (Ppy) and anthraquinone 2-sulfonate (AQS) (PCF/Ppy/AQS) for an efficient electro-Fenton process has been investigated. Brunauer Emmett Teller (BET) and scanning electron microscope (SEM) measurements verified the three-dimensional porous structure of the PCF, revealing that the specific surface area was approximately 2.5 times higher than that of the bare carbon felt (CF), which ensured more active sites available for oxygen reduction reaction (ORR). In addition, the electrodeposited Ppy decreases the charge transfer resistance (Rct) of the PCF cathode. AQS, a type of anthraquinone that can serve as an oxygen reduction catalyzer, could accelerate the ORR process and subsequently improve the performance of the electro-Fenton system. Rotating disk electrode (RDE) analysis confirmed that the ORR catalyzed by AQS was a double-electron reduction process, which contributed to hydrogen peroxide (H2O2) generation. The removal efficiency of total organic carbon (TOC) from Rhodamine B (RhB) could reach 51% within 1 h in the electro-Fenton system equipped with the PCF/Ppy/AQS, resulting in an improvement of approximately 24% compared with the bare CF cathode without porous treatment. The cycle experiment showed a good stability of the PCF/Ppy/AQS cathode. Additionally, the possible mechanism of degradation process in the electro-Fenton equipped with the PCF/Ppy/AQS cathode was proposed based on the electron paramagnetic resonance (EPR) analysis and quenching experiment. The novel fabricated PCF/Ppy/AQS provides an alternative as a high-efficiency cathode, yielding energy savings in the electro-Fenton system. 相似文献
7.
8.
《International Journal of Hydrogen Energy》2020,45(3):1857-1866
In our previous research, titanium-based nitride with high conductivity and superior corrosion resistance were developed as an ideal core material for replacing noble metal to form Pt-based core-shell catalysts by pulse electrodeposition. Meanwhile, the smaller sizes of nitride cores would also be available for pulse electrodeposition by dispersing them on carbon nanotubes (CNT). To achieve a better practice on the preparation of the Pt-based core-shell catalysts, in this work, both nitrogen-doped carbon nanotubes (N-CNT) and reduced graphene oxide (N-rGO) were used to support the copper-doped titanium nitride (Ti0.9Cu0.1N) cores. In the course of pulse electrodeposition, their influences as supports on the electronic states of electrodeposited Pt as well as their catalytic activities were compared. The results showed that the Pt preferred to electrodeposit on Ti0.9Cu0.1N cores supported by N-CNT and formed a core-shell structure. While with the same electrodeposition process, the Pt was found to be electrodeposited not only on the Ti0.9Cu0.1N cores supported by N-rGO with heavy aggregations but also on the N-rGO support. Raman spectroscopy analysis indicated that the higher degree of structural defects on N-rGO, as support, might have contributed to such divergence observation. 相似文献
9.
在酸性体系中采用阴极扫描伏安和计时电流等电化学测试方法,研究添加十二烷基硫酸钠(SDS)对铜电沉积过程的影响机理。结果表明:SDS的添加使沉积电位正移,降低了阴极极化。SDS浓度低于临界胶束浓度1g/L时,铜的成核弛豫时间延长,形核速率降低。SDS浓度高于临界胶束浓度时,形成SDS球状胶束,铜的成核弛豫时间减少,形核速率加快。铜晶核形成过程符合Scharitker?Hill 三维成核/生长机制,当SDS为1g/L时,在-0.2V的低过电位区,铜结晶按渐进成核方式进行,在-0.23--0.28V的高过电位区,铜结晶按瞬时成核方式进行。而当SDS为0.5g/L时,铜在-0.2V--0.25V的低电位区和在-0.28V的高电位区均符合渐进成核。 相似文献
10.
Ibdal Satar Mimi Hani Abu Bakar Wan Ramli Wan Daud Nazlina Haiza Mohd Yasin Mahendra Rao Somalu Byung Hong Kim 《国际能源研究杂志》2020,44(9):7464-7476
The low cost, low over-potential loss, good catalytic properties for hydrogen evolution reaction (HER), high corrosion stability, commercially available, and could be applied in pH-neutral solution and ambient temperature are important properties for the cathode materials when it is applied in microbial electrolysis cell (MEC) technology. This study has two-pronged objectives: the first is to investigate the feasibility of titanium (Ti) and graphite felt (GF) coated with nickel (Ni), and the second is to generate hydrogen from the fermentation effluent (FE). The electrodeposition (ED) method was used to deposit Ni catalyst onto Ti (Ni/Ti) and GF (Ni/GF) surfaces. The scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy were used to characterize the cathode morphology and element composition. The catalytic properties of Ni/Ti and Ni/GF could be evaluated using the linear sweep voltammetry tests. The maximum volumetric H2 production rates of MEC using Ni/Ti and Ni/GF cathodes were obtained at 0.39 ± 0.01 and 0.33 ± 0.03 m3 H2 m−3 d−1 respectively. The Ni/Ti and Ni/GF cathodes could be used as alternative cathodes while producing hydrogen from FE. 相似文献