全文获取类型
收费全文 | 711篇 |
免费 | 42篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 3篇 |
综合类 | 3篇 |
化学工业 | 199篇 |
金属工艺 | 21篇 |
机械仪表 | 16篇 |
建筑科学 | 20篇 |
能源动力 | 51篇 |
轻工业 | 79篇 |
水利工程 | 5篇 |
石油天然气 | 7篇 |
无线电 | 76篇 |
一般工业技术 | 123篇 |
冶金工业 | 44篇 |
原子能技术 | 3篇 |
自动化技术 | 110篇 |
出版年
2024年 | 6篇 |
2023年 | 13篇 |
2022年 | 39篇 |
2021年 | 77篇 |
2020年 | 35篇 |
2019年 | 47篇 |
2018年 | 61篇 |
2017年 | 35篇 |
2016年 | 40篇 |
2015年 | 24篇 |
2014年 | 34篇 |
2013年 | 47篇 |
2012年 | 40篇 |
2011年 | 49篇 |
2010年 | 30篇 |
2009年 | 37篇 |
2008年 | 20篇 |
2007年 | 20篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1956年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有760条查询结果,搜索用时 500 毫秒
61.
Muhammad U. Farooq Xiangxue Zhang Yanan Guan Wenyao Chen Jinghong Zhou Jing Zhang Gang Qian Xuezhi Duan Xinggui Zhou Weikang Yuan 《American Institute of Chemical Engineers》2023,69(1):e17932
Methyl methacrylate (MMA) is an important monomer for the production of acrylic plastics and polymer dispersions. In this study, we demonstrate a strategy to synergize the electronic and geometric effects of the Au/CeO2 catalyst, achieving three orders of magnitude improvement in reaction rate for the oxidative esterification of methacrolein to MMA. The electronic properties of Au in terms of the valence electron population of 5d states are decoupled from the redox ability and acid–base properties of catalyst support as the main cause for the significant increase in the specific activity of the active site. Moreover, the Au edge site is identified as the main active site for this reaction, whose number reaches the maximum for the 1.6 nm-sized Au particles. Hence, the synergism between the electronic (lower valence electron population of 5d states) and geometric (more edge active sites) promotions of the Au-10/CeO2 catalyst contributes to the highest catalytic activity. 相似文献
62.
Effects of Guar–Xanthan Gum Mixture as Fat Replacer on the Physicochemical Properties and Oxidative Stability of Goshtaba,a Traditional Indian Meat Product
下载免费PDF全文
![点击此处可从《Journal of Food Processing and Preservation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
63.
Prediction of friction coefficient of treated betelnut fibre reinforced polyester (T-BFRP) composite using artificial neural networks 总被引:2,自引:1,他引:1
Umar Nirmal 《Tribology International》2010,43(8):1417-1429
The current work is an attempt of using artificial neural network configuration to predict frictional performance of treated betelnut fibre reinforced polyester (T-BFRP) composite. Experimental dataset at different applied loads (5-30 N) and sliding distances (0-6.72 km) was used to train the ANN configuration with a large volume of experimental data (492 sets) where three different fibre mat orientations were considered (anti parallel, parallel and normal orientations). Results obtained from the developed ANN model were compared with experimental results. It is found that the experimental and numerical results showed good accuracy when the developed ANN model was trained with Levenberg-Marqurdt training function. 相似文献
64.
Farooq A. Khanday Costas Psychalinos Nisar A. Shah 《Circuits, Systems, and Signal Processing》2013,32(3):959-978
Square-root-domain (SRD) CMOS analog realization of a single cell architecture of the complex Temporal Derivative Cellular Neural Networks (TDCNNs) is introduced in this paper. TDCNN initiates time derivative ‘diffusion’ between CNN cells for non-separable spatiotemporal filtering applications, where the input to the CNN is an image that changes over time. The evaluation of the performance of the complex SRD TDCNN cell has been done using the Cadence Orcad software with TSMC 0.18-μm CMOS process model parameters. The provided simulated results confirm the validity of the theory. 相似文献
65.
Wei Shi Lei Wang Mavluda Umar Tunsagul Awut Hongyu Mi Chong Tan Ismayil Nurulla 《Polymer International》2009,58(7):800-806
BACKGROUND: Various poly(arylene ethynylene)s (PAEs) have been prepared and applied as molecular wires, in sensors, in nonlinear optics and as electroluminescent materials. But, to our knowledge, there has been no attention paid to the investigation of conjugated PAEs containing both triarylamine and quinoxaline groups. The influence imparted by the introduction of triarylamine and quinoxaline on the photophysical and electrochemical properties of PAEs is of interest. RESULTS: Two kinds of novel PAE derivatives, with electron‐donating triphenylamine groups in the backbone and electron‐accepting pendent quinoxaline moieties and bearing side chains of different lengths, were successfully synthesized with the Sonogashira coupling reaction. These polymers are soluble in common organic solvents and exhibit good film‐forming ability and thermal stability. UV‐visible investigations indicate that the ground states of these materials are unaffected by the polarity of their medium. An efficient intramolecular charge transfer effect is observed from an investigation of their photoluminescence properties in different solvents. Cyclic voltammetry study reveals that these polymers possess relatively high highest occupied molecular orbital levels due to the incorporation of triphenylamine segments into the polymer backbones. CONCLUSION: Primary characterization of these novel PAE derivatives shows that they might serve as potential active materials in optoelectronic devices. Copyright © 2009 Society of Chemical Industry 相似文献
66.
67.
Thin films of cobalt(II) oxyhydroxide on platinum have been prepared by electrodeposition. The chemical diffusion coefficient D of the hydroxide ion through the material has a marked temperature dependence, showing a simple activated behaviour in the range 273–292 K. The activation energy to ionic movement was rather large at 54.5 kJ mol–1 which, it is proposed, is ascribable to ion hopping. When spins have changed alignment, at the Néel transition temperature T
Nr
the activation energy more than doubled to 125 kJ mol–1; and the diffusion coefficients obtained above this temperature also increased dramatically. It is proposed that structural changes occur in the electrodeposited oxide at about T
Nr
hence the change in activation energy. 相似文献
68.
69.
The objective of this study was to formulate and develop a good quality cottage cheese dressing using acid whey as the main ingredient. Up to 72% of cottage cheese whey was used in the dressing mixes. The percentage of fat (4.10–5.05%) and total solids (19.41–20.24%) approached the desired level and was within the legal limits for regular cottage cheese. Sensory evaluation scores for flavour, body/texture and appearance were not adversely affected by the use of acid whey. The sensory evaluation scores for all four products made with whey- or skimmed milk-based dressings were higher than the commercial control. 相似文献
70.