全文获取类型
收费全文 | 234篇 |
免费 | 14篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 41篇 |
机械仪表 | 7篇 |
建筑科学 | 20篇 |
矿业工程 | 1篇 |
能源动力 | 7篇 |
轻工业 | 23篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 16篇 |
一般工业技术 | 42篇 |
冶金工业 | 44篇 |
原子能技术 | 1篇 |
自动化技术 | 37篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 9篇 |
2013年 | 14篇 |
2012年 | 9篇 |
2011年 | 13篇 |
2010年 | 18篇 |
2009年 | 13篇 |
2008年 | 12篇 |
2007年 | 8篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1975年 | 1篇 |
1968年 | 1篇 |
1960年 | 1篇 |
1948年 | 1篇 |
1942年 | 1篇 |
排序方式: 共有248条查询结果,搜索用时 31 毫秒
1.
The role of carbon deposition on precious metal catalyst activity during dry reforming of biogas 总被引:1,自引:0,他引:1
Federico Barrai Tracy Jackson Noah Whitmore Marco J. Castaldi 《Catalysis Today》2007,129(3-4):391-396
Gold and palladium were supported on a mesoporous TiO2 for total oxidation of volatile organic compounds (VOCs). Mesoporous high surface area titania support was synthesised using of Ti(OC2H5)2 in the presence of CTMABr surfactant. After removing the surfactant molecules, 0.5 or 1.5 wt% of palladium and 1 wt% of gold were precipitated on the support by, respectively, wet impregnation and deposition–precipitation methods. The activity for toluene and propene total oxidation of the prereduced samples follows the same order: 0.5%Pd-1%Au/TiO2 > 1.5%Pd/TiO2 > 0.5%Pd/TiO2 > 1%Au-0.5%Pd/TiO2 > 1%Au/TiO2 > TiO2. Moreover, a catalytic comparison with samples based on a conventional TiO2, shows the catalytic advantage of the mesoporous TiO2 support. The promotional effect of gold added to palladium could be partly explained by small metallic particles (TEM), but meanly by metallic particles made up of Au-rich core with a Pd-rich shell. Moreover, the hydrogen TPR profile of 0.5%Pd-1%Au/TiO2 shows only the signal attributed to small PdO particles. Gold also implies a protecting effect of the support under reduction atmosphere. Operando diffuse reflectance infrared fourier transform (DRIFT) spectroscopy was carried on and allowed to follow the VOCs oxidation and the formation of coke molecules, but also a metallic electrodonor effect to the adsorbed molecule which increases in the same order as the activity for oxidation reaction. The presence of coke after test was also shown by DTA–TGA by exothermic signals between 300 and 500 °C and by EPR (g = 2.003). 相似文献
2.
3.
Kofi E. Aidoo Richard F. Tester Janet E. Morrison & David MacFarlane 《International Journal of Food Science & Technology》1996,31(5):433-438
Composition and microbiological contamination was measured in samples of pre-packed dates purchased from a number of stores and retail outlets in Greater Glasgow. The sugar content of dried pitted dates was c . 74%, about 10% more than reported on those packs where nutritional information was given. Potentially pathogenic bacteria like Escherichia coli, Staphylococcus aureus and Bacillus cereus were identified in some of the samples together with lactic acid bacteria, yeasts and moulds, Aspergillus flavus and A. parasiticus . Fresh dates were the most heavily contaminated of all samples, probably owing to the high moisture content. 相似文献
4.
Lyndsay A. Cartwright Sue Hayes Douglas C. Tozer Dan Clayton Mary-Ann Burns Dena Lewis Noah Gaetz Namrata Shrestha 《Journal of Great Lakes research》2021,47(2):273-282
Beneficial use impairments (BUIs) under the Great Lakes Water Quality Agreement identify environmental issues requiring remedial action within the Great Lakes Areas of Concern (AOCs). We conducted this study to support the assessment of the wildlife component of BUI 3: degradation of fish and wildlife populations. We compared bird and amphibian (frogs and toads) data from the Toronto and Region Conservation Authority’s Terrestrial Long-term Monitoring Program in the Toronto and Region AOC to an adjacent, but otherwise similar, reference watershed, Duffins Creek. Twelve of 13 targets were met within the AOC for forest bird, wetland bird, meadow bird and amphibian populations based on averages of mean annual values at sites within the AOC that were within two standard deviations of averages at sites in the Duffins Creek reference watershed between 2008 and 2017. Even though wildlife populations within the AOC were within the normal range of variability expected from a reference watershed, they were often at lower levels than within the Duffins Creek reference watershed. In addition, forest bird and amphibian populations were negatively affected by urbanization within the AOC and meadow bird indices declined. We conclude that while wildlife populations within the AOC currently meet targets for BUI 3, they continue to be negatively impacted by numerous stressors that are primarily related to past and ongoing urbanization. Thus, continued restoration of wildlife habitat and protection of existing habitat within the AOC is highly recommended. 相似文献
5.
Natalya N. Barabanova Victor V. Belyaev Dmitriy L. Bogdanov Vladimir G. Chigrinov Artem K. Dadivanyan Artem P. Nazarov Olga V. Noah 《Journal of the Society for Information Display》2015,23(10):486-490
A method of controlling anchoring energy of surface interaction of liquid crystal photoaligning substances is considered to enhance the liquid crystal display performances. An important parameter of the dye's molecular structure that determines the ratio of polar and azimuthal anchoring energy is the ability to form dimers. The values of dimerization thermodynamic potentials have been found. The probability of the formation of dye molecules dimers is evaluated. The bonds conjugation transfer via intermolecular hydrogen bond is revealed, and anisotropy of polarizability of the hydrogen bond is evaluated. The effect of dimerization on polar and azimuthal anchoring energy of liquid crystal — azo dye system — is shown. 相似文献
6.
7.
Shijie Hu Xiaoyu Li Jiayu Bai Hang Lei Weizhong Qian Sunqiang Hu Cong Zhang Akpatsa Samuel Kofi Qian Qiu Yong Zhou Shan Yang 《计算机、材料和连续体(英文)》2023,74(2):2803-2815
When the Transformer proposed by Google in 2017, it was first used for machine translation tasks and achieved the state of the art at that time. Although the current neural machine translation model can generate high quality translation results, there are still mistranslations and omissions in the translation of key information of long sentences. On the other hand, the most important part in traditional translation tasks is the translation of key information. In the translation results, as long as the key information is translated accurately and completely, even if other parts of the results are translated incorrect, the final translation results’ quality can still be guaranteed. In order to solve the problem of mistranslation and missed translation effectively, and improve the accuracy and completeness of long sentence translation in machine translation, this paper proposes a key information fused neural machine translation model based on Transformer. The model proposed in this paper extracts the keywords of the source language text separately as the input of the encoder. After the same encoding as the source language text, it is fused with the output of the source language text encoded by the encoder, then the key information is processed and input into the decoder. With incorporating keyword information from the source language sentence, the model’s performance in the task of translating long sentences is very reliable. In order to verify the effectiveness of the method of fusion of key information proposed in this paper, a series of experiments were carried out on the verification set. The experimental results show that the Bilingual Evaluation Understudy (BLEU) score of the model proposed in this paper on the Workshop on Machine Translation (WMT) 2017 test dataset is higher than the BLEU score of Transformer proposed by Google on the WMT2017 test dataset. The experimental results show the advantages of the model proposed in this paper. 相似文献
8.
9.
Laser-induced fluorescence (LIF) measurements have been performed for the first time in a low temperature (Te approximately 0.6 eV) Xe plasma using a tunable diode laser in the visible range of wavelengths. The transition in Xe II involved the (3P1)5d[3]7/2 metastable state and the excitation wavelength was found to be 680.570+/-0.001 nm (air). LIF measurements of I 2 in a room temperature iodine gas cell were used to monitor the wavelength of the laser during the measurements. 相似文献
10.
Francis Kofi Andoh-Baidoo Kweku-Muata Osei-Bryson Kwasi Amoako-Gyampah 《Information Systems Frontiers》2012,14(2):237-259
We explore the theoretical foundations on how firm and IT characteristics explain the market value variations in e-commerce
initiatives by examining the announcements of 946 e-commerce initiatives in the public media. Our approach combines the Event
study methodology and Decision tree induction to examine the main and interaction effects of IT and firm characteristics on
Cumulative Abnormal Returns (CAR). In particular, we generate complex interaction models that can guide e-commerce investment
decisions so managers can know, for example, which combination of IT and firm characteristics are more likely to be viewed
positively by investors. The selected study variables as well as explanation of the proposed framework are informed by innovation,
resource-based view, transaction cost economics and complementarity theories. We have inductively developed a set of propositions
that can be deductively tested to assess the validity of our proposed theoretical framework. Hence our study provides an initial
roadmap for theory development on e-commerce and CAR. 相似文献