全文获取类型
收费全文 | 111篇 |
免费 | 9篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 3篇 |
综合类 | 11篇 |
化学工业 | 28篇 |
金属工艺 | 2篇 |
机械仪表 | 3篇 |
建筑科学 | 10篇 |
矿业工程 | 3篇 |
能源动力 | 5篇 |
轻工业 | 10篇 |
水利工程 | 2篇 |
石油天然气 | 5篇 |
武器工业 | 2篇 |
无线电 | 13篇 |
一般工业技术 | 10篇 |
冶金工业 | 6篇 |
原子能技术 | 1篇 |
自动化技术 | 18篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 8篇 |
2014年 | 9篇 |
2013年 | 10篇 |
2012年 | 11篇 |
2011年 | 4篇 |
2010年 | 7篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2007年 | 4篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1990年 | 1篇 |
排序方式: 共有132条查询结果,搜索用时 15 毫秒
2.
3.
全球传统石化能源耗竭及气候变迁等负面效应日益严重,以永续发展为目标,再生能源之开发利用备受关注,已成为世界各国能源政策的主要施政方针,其中多以立法手段积极推动.综观各国已提出亦或正在施行的政策和措施,皆由订定法令来体现,以法律的形式确立发展目标,再透过具体而明确的强制规范或经济激励措施,进而得其实质成效.德国再生能源法相关法规范即为明证.德国于2000年制定全球首部再生能源优先法(Gesetz fürden Vorrang Erneuerbarer Energien),简称再生能源法(Ernererbare-Energien-Gesetz,EEG),至今已历多次修法.本文将从德国再生能源法制探讨,观其核心固定电价制度(Feed-in Tariff,FIT)与近年修法方向,说明德国再生能源产业发展之背景及现况,希祈能就推动发展再生能源有所帮助. 相似文献
4.
溶聚丁苯橡胶技术进展 总被引:3,自引:0,他引:3
从引发剂,偶联剂,改性及聚合工艺等诸方面介绍了2000年溶聚丁苯橡胶技术新进展,并对其在21世纪的发展方向进行了展望。 相似文献
5.
An Paenhuysen 《History of Photography》2013,37(1):39-54
This essay analyses Kurt Tucholsky and John Heartfield's 1929 Deutschland, Deutschland über Alles. In this ‘picture‐book’ right‐wing nationalism, the military, the democratic system, and capitalism were trenchantly criticized. This essay argues, however, that Deutschland, Deutschland über Alles is as much about the role of photography in society as it is about Weimar's political situation. The late 1920s are generally seen as a period of medium optimism in which the new photography was in the forefront. Yet a close analysis of the use of photography in Deutschland, Deutschland über Alles nuances the so‐called optimism of Weimar visual culture and its sudden disruption by the advent of fascism in the 1930s. While from the early 1910s onwards, Tucholsky had promoted the polemical power of photography, his position shifted by the end of the 1920s. An ambivalence marked Deutschland, Deutschland über Alles: on the one hand the photographic medium was used as a critical tool; on the other, the book reflects an underlying critique of and frustration with photojournalism and its association with urban modernity. 相似文献
6.
Mohammadreza Kosari Uzma Anjum Shibo Xi Alvin M. H. Lim Abdul Majeed Seayad Emmanuel A. J. Raj Sergey M. Kozlov Armando Borgna Hua Chun Zeng 《Advanced functional materials》2021,31(47):2102896
Beyond the catalytic activity of nanocatalysts, the support with architectural design and explicit boundary could also promote the overall performance through improving the diffusion process, highlighting additional support for the morphology-dependent activity. To delineate this, herein, a novel mazelike-reactor framework, namely multi-voids mesoporous silica sphere (MVmSiO2), is carved through a top-down approach by endowing core-shell porosity premade Stöber SiO2 spheres. The precisely-engineered MVmSiO2 with peripheral one-dimensional pores in the shell and interconnecting compartmented voids in the core region is simulated to prove combined hierarchical and structural superiority over its analogous counterparts. Supported with CuZn-based alloys, mazelike MVmSiO2 nanoreactor experimentally demonstrated its expected workability in model gas-phase CO2 hydrogenation reaction where enhanced CO2 activity, good methanol yield, and more importantly, a prolonged stable performance are realized. While tuning the nanoreactor composition besides morphology optimization could further increase the catalytic performance, it is accentuated that the morphological architecture of support further boosts the reaction performance apart from comprehensive compositional optimization. In addition to the found morphological restraints and size-confinement effects imposed by MVmSiO2, active sites of catalysts are also investigated by exploring the size difference of the confined CuZn alloy nanoparticles in CO2 hydrogenation employing both in-situ experimental characterizations and density functional theory calculations. 相似文献
7.
Rochow-Müller反应是一种直接合成甲基氯硅烷的方法。由于其原料易得,产物收率高,工艺较易实现,成为有机硅工业单体生产的主流工艺。到目前为止,铜基催化剂仍为Rochow-Müller反应的核心催化剂,催化性能的改善对该工艺的提升具有重大意义。在探索高效催化剂和理解其机理方面已取得相关进展,但由于副产物多,复杂性高,对该反应真实反应路径的追踪仍然较为困难。对Rochow-Müller反应的热力学过程、铜基催化剂及助催化剂的应用、反应机制及动力学过程和工艺条件的影响进行综述讨论。希望这项工作能够准确地反应Rochow-Müller反应催化工艺的最新进展,并可以促进有机硅工业的可持续性发展。 相似文献
8.
Yinteng Shi Lin Ai Haonan Shi Xiaoyu Gu Yujun Han Jixiang Chen 《Frontiers of Chemical Science and Engineering》2022,16(4):443
Carbon-coated Ni, Co and Ni-Co alloy catalysts were prepared by the carbonization of the metal doped resorcinol-formaldehyde resins synthesized by the one-pot extended Stöber method. It was found that the introduction of Co remarkably reduced the carbon microsphere size. The metallic Ni, Co, and Ni-Co alloy particles (mainly 10–12 nm) were uniformly distributed in carbon microspheres. A charge transfer from Ni to Co appeared in the Ni-Co alloy. Compared with those of metallic Ni and Co, the d-band center of the Ni-Co alloy shifted away from and toward the Fermi level, respectively. In the in-situ aqueous phase hydrodeoxygenation of methyl palmitate with methanol as the hydrogen donor at 330 °C, the decarbonylation/decarboxylation pathway dominated on all catalysts. The Ni-Co@C catalysts gave higher activity than the Ni@C and Co@C catalysts, and the yields of n-pentadecane and n-C6–n-C16 reached 71.6% and 92.6%, respectively. The excellent performance of Ni-Co@C is attributed to the electronic interactions between Ni and Co and the small carbon microspheres. Due to the confinement effect of carbon, the metal particles showed high resistance to sintering under harsh hydrothermal conditions. Catalyst deactivation is due to the carbonaceous deposition, and the regeneration with CO2 recovered the catalyst reactivity. 相似文献
9.
10.
针对多线结构光系统的快速标定,提出了一种基于普吕克直线的标定方法。传统的线结构光标定方法大多以单点的形式进行提取和坐标系转换,从而获得平面方程。然而单点数量较多会导致操作复杂,不适用于多线结构光的标定。为了解决这个问题,提出了一种新的标定方法,该方法在标定过程中全部采用普吕克矩阵的形式,而不是直接使用点特征。该方法有利于在摄像机坐标系下快速准确地获得光平面方程。同时设计了一种与该方法相对应的用于标定多线结构光的平面标定靶标。为了将一般直线转换为普吕克直线,将图像平面维度延展,定义了一个新的图像空间。为了对普吕克直线的坐标系进行转换,重新表达了基于普吕克直线的透视投影模型。基于普吕克空间中直线与平面的性质,对多条结构光线的普吕克矩阵进行合并即可高效地构造出线性的矩阵方程,从而进一步拟合出结构光平面方程。实验验证了所提方法并证明了校准精度的显著提高,当测试距离为1.8 m时,测量得到的三维点的RMS误差在0.08 mm之内。 相似文献