全文获取类型
收费全文 | 179篇 |
免费 | 20篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 6篇 |
综合类 | 23篇 |
化学工业 | 27篇 |
金属工艺 | 13篇 |
机械仪表 | 9篇 |
建筑科学 | 10篇 |
矿业工程 | 5篇 |
能源动力 | 3篇 |
轻工业 | 4篇 |
水利工程 | 3篇 |
石油天然气 | 8篇 |
武器工业 | 8篇 |
无线电 | 20篇 |
一般工业技术 | 17篇 |
冶金工业 | 33篇 |
自动化技术 | 12篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 6篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 2篇 |
2012年 | 4篇 |
2011年 | 10篇 |
2010年 | 5篇 |
2009年 | 9篇 |
2008年 | 15篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
排序方式: 共有201条查询结果,搜索用时 11 毫秒
11.
William D. Pyrz Douglas A. Blom N. Raveendran Shiju Vadim V. Guliants Thomas Vogt Douglas J. Buttrey 《Catalysis Today》2009,142(3-4):320
We use aberration corrected high-angle annular dark field (HAADF) imaging to systematically study, atomic column by atomic column, the effects of substituting Nb or Ta into the M1 phase of the MoV(Nb,Ta)TeO propane (amm)oxidation catalyst. The HAADF results indicate that the x,y coordinates of the metal sites within the M1 framework are unaffected by the substitution of either Nb or Ta for Mo. The HAADF analysis of the Ta-substituted catalyst demonstrated that the Ta preferentially substitutes into the pentagonal bipyramidal site, and by analogy, we anticipate that Nb substitutes similarly. Compositional analysis of the entire framework suggests that Ta/Nb behaves as a director of V among the octahedra that link the pentagonal rings, and the variable V occupancy may be correlated with variations in catalytic activities and selectivities. Finally, HAADF imaging provided evidence of coexistence of Ta-rich and Ta-poor domains. Similar phase segregation behavior may be present in Nb-substituted specimens, but would be very difficult to detect. 相似文献
12.
高士驹 《青岛大学学报(工程技术版)》1988,(2)
本文对低马强化的工艺特点和影响因素进行了综合归纳与分析,并提出了此种工艺的合理应用范围,为该工艺的推广应用提供了重要的参考依据。 相似文献
13.
Fabrication and compressive performance of plain carbon steel honeycomb sandwich panels 总被引:1,自引:0,他引:1
Yu'an Jing Shiju Guo Jingtao Han Yufei Zhang Weijuan Li 《北京科技大学学报(英文版)》2008,15(3):255-260
Plain carbon steel Q215 honeycomb sandwich panels were manufactured by brazing in a vacuum furnace.Their character- istic parameters,including equivalent density,equivalent elastic modulus,and equivalent compressive strength along out-of-plane (z-direction)and in-plane(x- and y-directions),were derived theoretically and then determined experimentally by an 810 material test system.On the basis of the experimental data,the compressive stress-strain curves were given.The results indicate that the meas- urements of equivalent Young's modulus and initial compressive strength are in good agreement with calculations,and that the maximum compressive strain near to solid can be up to 0.5-0.6 along out-of-plane,0.6-0.7 along in-plane.The strength-to-density ra- tio of plain carbon steel honeycomb panels is near to those of Al alloy hexagonal-honeycomb and 304L stainless steel square-honeycomb,but the compressive peak strength is greater than that of Al alloy hexagonal-honeycomb. 相似文献
14.
15.
16.
本文论述了在实验室对红麻全杆及芯杆分别试制牛皮箱纸板的研究.研究结果表明:红麻全杆及芯杆经适宜的化学方法和工艺条件处理后,经高浓磨浆制得的半化学浆以不同的配比代替本色木浆挂面,试制的牛皮箱纸板各项技术指标均可达到国家标准要求. 相似文献
17.
Two indolo[3,2-b]carbazole (ICZ)-based polymers have been designed and synthesized using Sonogashira cross-coupling based on dibromoindolo[3,2-b]carbazoles and 2,7-diethynylfluorene or 9,10-diethynylanthracene. The 2, 8 positions of the ICZ moiety has been used for the bridging of arylene ethynylene structure to form the polymer backbone. The characterization has been done by Fourier transform infrared, proton nuclear magnetic resonance, ultraviolet–visible and (UV–vis) fluorescence spectroscopic methods. The polymers, moderately soluble in aprotic and chlorinated solvents, have been found to possess thermal stability above 300°C. The band gap examinations, executed through cyclic voltammetry and complemented by UV–vis studies, indicated their semiconducting nature and the possibility for their utilization for the fabrication of polymer solar cells and for optical switching applications. Interestingly, the new diethynylindolocarbazole systems have been found to act as Bronsted acid sensors as well as a Hg2+ receptors. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46940 相似文献
18.
Julie Garvey David Newport Fereydoun Lakestani Maurice Whelan Shiju Joseph 《Microfluidics and nanofluidics》2008,5(1):77-87
This paper presents micro-interferometry as a measurement technique to extract temperature profiles and/or mass transfer gradients
rapidly and locally in micro-devices. Interferometry quantifies the phase change between two or more coherent light beams
induced by temperature and/or mass concentration. Previous work has shown that temporal noise is a limiting factor in microscale
applications. This paper examines phase stepping and heterodyne phase retrieval techniques with both CCD and CMOS cameras.
CMOS cameras are examined owing to the high speed at which images can be acquired which is particularly relevant to heterodyne
methods. It is found that heterodyne retrieval is five times better than phase stepping being limited to 0.01 rad or λ/628.
This is twice the theoretical limit of λ/1,000. The technique is demonstrated for mixing in a T-junction with a 500 μm square
channel and compared favourably to a theoretical prediction from the literature. Further issues regarding application to temperature
measurements are discussed. 相似文献
19.
20.