全文获取类型
收费全文 | 426篇 |
免费 | 56篇 |
国内免费 | 76篇 |
专业分类
电工技术 | 11篇 |
综合类 | 18篇 |
化学工业 | 94篇 |
金属工艺 | 15篇 |
机械仪表 | 56篇 |
建筑科学 | 6篇 |
矿业工程 | 3篇 |
能源动力 | 19篇 |
轻工业 | 12篇 |
水利工程 | 3篇 |
石油天然气 | 9篇 |
武器工业 | 55篇 |
无线电 | 55篇 |
一般工业技术 | 57篇 |
冶金工业 | 9篇 |
原子能技术 | 70篇 |
自动化技术 | 66篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 14篇 |
2021年 | 21篇 |
2020年 | 22篇 |
2019年 | 28篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 9篇 |
2014年 | 15篇 |
2013年 | 48篇 |
2012年 | 64篇 |
2011年 | 50篇 |
2010年 | 30篇 |
2009年 | 49篇 |
2008年 | 40篇 |
2007年 | 60篇 |
2006年 | 31篇 |
2005年 | 14篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1987年 | 1篇 |
1982年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有558条查询结果,搜索用时 15 毫秒
41.
二维过渡金属碳化物(MXenes)具有良好的电化学性能与辐照稳定性, 其在放射性核素电化学检测领域有潜在应用价值。本研究通过碱活化的方式处理碳化钛型MXene(Ti3C2Tx), 随后将钾插层的Ti3C2Tx(K-Ti3C2Tx)负载到玻碳电极(GCE)上得到K-Ti3C2Tx/GCE修饰电极。采用XRD、SEM、XPS等手段分别对Ti3C2Tx和K-Ti3C2Tx进行分析表征, 并进一步研究了K-Ti3C2Tx/GCE对痕量铀酰离子(UO22+)的电化学检测性能。循环伏安(CV)实验结果表明, 相比于GCE电极, K-Ti3C2Tx/GCE修饰电极对UO22+的电化学响应显著增强。进一步使用差分脉冲伏安法(DPV)扫描, 发现pH=4.0时, K-Ti3C2Tx/GCE修饰电极对UO22+在铀浓度0.5~10 mg/L范围内呈现良好的线性检测关系, 本方法的检测限为0.083 mg/L(S/N=3), 稳定性和重复性好。 相似文献
42.
《International Journal of Hydrogen Energy》2020,45(38):19493-19504
2LiH + MgB2 composite doped with TiO2 (Li-RHC-Ti) is employed with a two-fold purpose: hydrogen purification under a H2–CO (0.1 mol%) mixture and CO methanation. Upon dynamic cycling under CO–H2 mixture, hydrogen release curves display a quite stable amount of pure hydrogen of about 10 wt%, short release times of around 60 min, and minor degradation. Gas analysis by Fourier transform infrared spectroscopy (FTIR) after a thermal dehydrogenation process of MgH2 and LiBH4 under CO evidence the conversion of CO to CH4. Li-RHC-Ti dehydrogenated under CO shows the simultaneous formation of CH4, CH3OH, and B(CH3)3 in the gas phase. X-ray powder diffraction (XRPD) and FTIR characterizations of the solid phases of Li-RHC-Ti after both H2–CO mixture and CO interactions demonstrate the formation of MgO, LiBO2, and HCOO− species. Li-RHC-Ti acts as a hydrogen source and promoter for the CO conversion. Reaction pathways are proposed based on experimental results and equilibrium composition calculations. 相似文献
43.
44.
氡及其子体对公众的辐射照射占天然辐射照射的一半以上,而室内氡子体未结合态份额是影响氡子体剂量转换系数的重要参数。为探究氡子体未结合态份额的变化及受室内外环境因素的影响规律,本研究采用自行开发的累积式氡子体未结合态份额采样装置,在北京大学技物楼室内外环境中开展了氡子体未结合态份额的年变化测量,并利用商用连续式氡子体测量仪测量了室内氡子体未结合态份额的日变化。实测结果表明:在室内和室外不同环境中,氡子体未结合态份额的年平均值分别为8.8%(6.4%~12.5%)和9.7%(4.9%~12.8%);室内环境中氡子体未结合态份额相对稳定;室外环境中氡子体未结合态份额受环境因素影响大,波动较大;关于日变化,虽然室内平衡当量氡子体浓度呈现出明显的上午高下午低的日变化规律,但没有观察到未结合态份额有规律性的日变化。 相似文献
45.
46.
化工生产过程普遍存在间歇过程多、自动化程度低、工艺复杂、条件苛刻、危险性高等特点。传统的过程研究及开发手段风险大、周期长,需要消耗大量的人力、物力、财力。而利用现代仿真技术建立一套虚拟生产系统,人们可在没有危险的情况下从事相关科研工作;节省实际研究中所需的高额成本;动态搭建并分析反应流程,优化工艺参数,加快整个化工生产研究的进程;与搭建的流程进行人机交互,实时观察各相关设备的工作状态和反应现象;可人为设置故障点,或改变工艺参数, 为应急演练和操作培训提供一种新的思路和实践;为开展化工流程模拟、仿真培训与生产过程可视化监控提供有效的支持。本文介绍了最近国内外在现代化工仿真技术领域取得的进展并探讨了其未来的发展趋势。 相似文献
47.
Zhiyun Zou Dandan Zhao Xinghong Liu Yuqing Guo Chen Guan Wenqiang Feng Ning Guo 《中国化学工程学报》2015,23(8):1364-1368
By taking advantage of the separation characteristics of nonlinear gain and dynamic sector inside a Hammerstein model, a novel pole placement self tuning control scheme for nonlinear Hammerstein system was put forward based on the linear system pole placement self tuning control algorithm. And the nonlinear Hammerstein system pole placement self tuning control (NL-PP-STC) algorithm was presented in detail. The identification ability of its parameter estimation algorithm of NL-PP-STC was analyzed, which was always identifiable in closed loop. Two particular problems including the selection of poles and the on-line estimation of model parameters, which may be met in applications of NL-PP-STC to real process control, were discussed. The control simulation of a strong nonlinear pH neutralization process was carried out and good control performance was achieved. 相似文献
48.
Fluorescent microspheres of polystyrene-based Eu(Ⅲ) complexes were prepared from TentaGel resin,2,6-bisbenzimidazolylpyri-dine and europium nitrate. The microspheres were characterized by FTIR spectroscopy, elemental analysis, XPS measurements and fluores-cence spectroscopy. Characteristic red emission under irradiation of365nm light from a hand-held UV lamp was observed for the micro-spheres either in a solution or solid-state.Fluorescent quenching was observed when the microspheres were exposed to a trace amount of di-ethyl chlorophosphate (DCP)in the dispersion. The material and property can be potentially used to fabricate chemosensor in the detection of organophosphates. 相似文献
49.
50.
Experiment and Analysis on the Treatment of Gaseous Benzene Using Pulsed Corona Discharge Plasma 总被引:2,自引:0,他引:2
An experiment and analysis on removal of gaseous benzene by pulse corona inducedplasma is presented in this article. Important parameters effecting removal efficiency have been investigated, such as pulse peak voltage, pulse frequency, gas inlet concentration, gas flow rate and reactor temperature. The result shows that the removal efficiency increases with the increase in pulse peak voltage, pulse frequency and reactor temperature, but decreases in the rise of gas inlet concentration and gas flow rate. On the condition of Vp = 36 kV, f = 80 Hz, C = 1440 mg/m^3 and Q = 640 ml/min, the largest removal efficiency is 98%. Finally, the reacted products are qualitatively analysed and the reaction processes are deduced in combination with plasma-chemistry theory. 相似文献