全文获取类型
收费全文 | 313篇 |
免费 | 82篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 29篇 |
综合类 | 12篇 |
化学工业 | 66篇 |
金属工艺 | 14篇 |
机械仪表 | 16篇 |
建筑科学 | 26篇 |
矿业工程 | 11篇 |
能源动力 | 8篇 |
轻工业 | 49篇 |
水利工程 | 11篇 |
石油天然气 | 22篇 |
武器工业 | 3篇 |
无线电 | 39篇 |
一般工业技术 | 48篇 |
冶金工业 | 6篇 |
原子能技术 | 2篇 |
自动化技术 | 46篇 |
出版年
2024年 | 11篇 |
2023年 | 35篇 |
2022年 | 53篇 |
2021年 | 68篇 |
2020年 | 38篇 |
2019年 | 27篇 |
2018年 | 18篇 |
2017年 | 23篇 |
2016年 | 15篇 |
2015年 | 19篇 |
2014年 | 17篇 |
2013年 | 20篇 |
2012年 | 11篇 |
2011年 | 17篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2002年 | 1篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
排序方式: 共有408条查询结果,搜索用时 0 毫秒
101.
World Wide Web - Clickbait is the use of an enticing title as bait to deceive users to click. However, the corresponding content is often disappointing, infuriating or even deceitful. This practice... 相似文献
102.
COVID-19 pandemic has accelerated the re-shaping of globalized manufacturing industry.Achieving a high level of resilience is thereby a recognized,essential ability of future manufacturing systems with the advances in smart manufacturing and Industry 4.0.In this work,a conceptual framework for resilient manufacturing strategy enabled by Industrial Internet is proposed.It is elaborated as a four-phase,closed-loop process that centered on proactive industry assessment.Key enabling technologies for the proposed framework are outlined in data acquisition and management,big data analysis,intelligent services,and others.Industrial Internet-enabled implementations in China in response to COVID-19 have then been reviewed and discussed from 3Rs'perspective,i.e.manufacturer capacity Recovery,supply chain Resilience and emergency Response.It is suggested that an industry-specific and comprehen-sive selection coordinated with the guiding policy and supporting regulations should be performed at the national,at least regional level. 相似文献
103.
104.
105.
煤炭燃烧与转化过程产生大量的固体废弃物粉煤灰,其大量排放与堆积造成的环境污染已引起人们的广泛重视,以粉煤灰为原料制备分子筛是粉煤灰资源化利用的重要途径。传统水热合成加热方式所需合成时间较长,能量消耗量大;微波加热可极大地缩短反应时间,并对产物晶粒大小、纯度和分子筛产品性能有明显改善。本文介绍了微波-水热合成法将粉煤灰转化为不同类型分子筛的反应机理及其所制备的分子筛产品的应用,分析了粉煤灰制备分子筛过程中阴离子和阳离子、前驱液的碱度、晶种、加热方式等关键因素的影响,讨论了粉煤灰经过分级处理和除杂后,用微波-水热相结合替代传统加热对分子筛产品纯度、晶粒尺寸、孔径分布的调控和优化规律,为粉煤灰合成不同种类分子筛提供了重要的理论指导与发展方向。同时提出了将煤粉炉粉煤灰经除杂和分级处理获取其中的硅铝组分、通过调控硅铝比以微波-水热合成制备方沸石的新工艺,为粉煤灰资源化利用开辟了新途径。 相似文献
106.
107.
以低品位钾长石为主要原料,碳化硅为发泡剂,通过高温发泡法制备多孔保温隔热陶瓷.分别采用X-射线衍射(XRD)和超景深显微成像对保温隔热陶瓷的晶相组成和结构形貌进行表征,研究了烧结温度与保温时间对多孔保温隔热陶瓷孔结构、导热系数、抗压强度、体积密度和吸水率等性能的影响.结果表明,烧结温度为1250℃、保温时间为30 min时制备的多孔陶瓷材料性能最优,样品的导热系数为0.072 W/(m·K),抗压强度为3.429 MPa,吸水率为13.5%,体积密度为0.542 g/cm3. 相似文献
108.
Qiqi Chen Yujian Liu Hangjun Deng Tingting Lyu Jing Tan Weimin Yang Haoyi Li Seeram Ramakrishna 《Polymer Engineering and Science》2020,60(11):2887-2894
Polyphenylene sulfide (PPS) nanofibers have broad application prospects in high temperature dust removal, high temperature oil-water separation, radiation protection, and other fields. PPS nanofibers were prepared by melt differential electrospinning without any other additives, which ensures the excellent properties of PPS fibers. The effects of spinning parameters (spinning voltage, spinning distance, spinning temperature) on the morphology of PPS fibers were systematically studied, and the average diameter of PPS fibers with 1.28 μm was obtained under the optimum conditions (spinning distance of 6 mm, temperature of 310°C and spinning voltage of 35 kV). The effect of spinning voltage on the crystallinity and thermal stability of the fiber was analyzed. Finally, the filtration efficiencies of the commercial dust-proof filter bags and the obtained PPS fibers with the same weight were compared. It was demonstrated that filtration efficiency of the obtained PPS fibers with 186 g/cm2 reached up to 99.95%. This study aims to provide a new idea for green industrial manufacturing and application of electrospinning PPS nanofibers. 相似文献
109.
为了探究涂层组分对整体式低温选择性催化还原(SCR)脱硝催化剂性能的影响,本文使用锰氧化物(MnO x )、氧化物涂层(TiO2、SiO2及Al2O3)、堇青石(CC)基体制备整体式涂层催化剂,考察催化剂牢固度以及脱硝活性。结果表明:在200℃ 时,对于MnO x /Al2O3/CC催化剂,MnO x 负载率为6%(质量分数)时脱硝效率最高为95%;对于MnO x /TiO2/CC,负载率为6%~12%时脱硝效率相差不大,为75%左右;对于MnO x /SiO2/CC,负载率12%时脱硝效率80%。样品牢固度排列顺序如下:MnO x /Al2O3/CC > MnO x /SiO2/CC > MnO x / TiO2 /CC。通过BET、SEM、TG、Raman、H2-TPR等测试与分析方法发现:影响催化剂性能的因素主要为活性组分MnO x 状态以及载体性能的差异。Al2O3涂层比表面积适中,作为载体活性好;SiO2涂层虽然比表面积大、牢固度好,但作为载体活性差;TiO2作为涂层比表面积较小,溶胶中溶剂挥发快使得涂层表面不均匀。 相似文献
110.
Bang LI Tingfeng MING Qing ZHUANG Feifei LONG Shanlu GAO Qiqi SHI Yumin WANG Xiaoju LIU Shaocheng LIU Long ZENG Xiang GAO 《等离子体科学和技术》2021,23(3):35104-75
A high-speed vacuum ultraviolet(VUV) imaging system has been developed on the Experimental Advanced Superconducting Tokamak(EAST), which selectively measures line emission with a central wavelength of 13.5 nm(CVI, n=4–2). It has been employed to study edge/pedestal plasma behavior in EAST. Edge localized mode(ELM)-induced filament structures have been captured by the VUV imaging system during the ELMy high confinement mode discharge with both high temporal and spatial resolutions. The typical features(i.e.poloidal width and pitch angle) of the observed filaments are quantitatively characterized based on the VUV imaging data, and the dependence of these features on basic plasma parameters is analyzed. It is found that the poloidal width is proportional to the heating power, and the pitch angle is inversely proportional to the edge safety factor q.95 The scatterplot shows a positive trend between the poloidal width and the ELM amplitude defined by the relative change in stored energy. These results are based on the condition that the perturbation induced by ELMs is confined to a narrow layer in the plasma. 相似文献