全文获取类型
收费全文 | 166篇 |
免费 | 13篇 |
学科分类
工业技术 | 179篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 10篇 |
2012年 | 7篇 |
2011年 | 8篇 |
2010年 | 14篇 |
2009年 | 10篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 8篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1991年 | 1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179条查询结果,搜索用时 15 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.
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
3.
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
4.
5.
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
6.
ABSTRACT Northwest Arkansas planning policies, like a number of communities across the country, have identified goals working toward more sustainable, livable, and subsequently denser development patterns. However, the understanding of residents’ perceptions of such living arrangements is limited. This study provides a more nuanced understanding of Northwest Arkansas residents’ spatial preferences through a survey of residents’ preferences for private amenities and their trade-off with various spatial densities and patterns in support of sustainability. Results of the survey indicate a preference for, and experience with, single-family residential living arrangements and amenities, with the preponderance (80%) of survey respondents currently living in single-family housing. There is a preference for low-density neighborhoods even if it means sacrificing other amenities. This study is in alignment with previous research suggesting that people may learn to prefer where they live. Additionally, while the majority of survey respondents indicated a preference for communal greenspaces, renters are more likely to prefer communal greenspaces when compared to homeowners. This study indicates that attached, multi-family development and renter development in Northwest Arkansas should consider the provision of communal green spaces, walkable access to transit, and walkable access to services as desired amenities for those residents. 相似文献
7.
8.
Moïse Nola Mireille E. Nougang Olive V. Noah Ewoti Luciane M. Moungang François Krier Nour‐Eddine Chihib 《Water and Environment Journal》2013,27(3):328-337
This study was aimed at assessing the prevalence of pathogenic Escherichia coli strains, relative to the total count of E. coli, faecal coliforms and other heterotrophic mesophilic aerobic bacteria (HMAB) isolated in groundwater in the equatorial region of Cameroon (Central Africa). Bacteria were isolated using standard methods. Pathogenic E. coli strains were then identified using haemagglutination and antisera tests. The maximum abundance of HMAB, faecal coliforms and E. coli strains were 4.9 × 106, 5.6 × 103 and 1 × 103 colony‐forming units (CFU)/100 mL, respectively. The count of pathogenic E. coli strains reached 3 CFU/100 mL. The counts of commensal and pathogenic E. coli strains underwent temporal and spatial fluctuations. In 21% of sampling sites, the abundance of faecal coliforms was significantly correlated to that of E. coli (P < 0.05). However, the isolated bacterial count was not significantly correlated to that of the pathogenic E. coli strains (P > 0.05). The bacteria abundance dynamics may be impacted by many interacting factors. 相似文献
9.
Abramowitz Jonathan S.; Deacon Brett J.; Olatunji Bunmi O.; Wheaton Michael G.; Berman Noah C.; Losardo Diane; Timpano Kiara R.; McGrath Patrick B.; Riemann Bradley C.; Adams Thomas; Bj?rgvinsson Thr?stur; Storch Eric A.; Hale Lisa R. 《Canadian Metallurgical Quarterly》2010,22(1):180
Although several measures of obsessive-compulsive (OC) symptoms exist, most are limited in that they are not consistent with the most recent empirical findings on the nature and dimensional structure of obsessions and compulsions. In the present research, the authors developed and evaluated a measure called the Dimensional Obsessive-Compulsive Scale (DOCS) to address limitations of existing OC symptom measures. The DOCS is a 20-item measure that assesses the four dimensions of OC symptoms most reliably replicated in previous structural research. Factorial validity of the DOCS was supported by exploratory and confirmatory factor analyses of 3 samples, including individuals with OC disorder, those with other anxiety disorders, and nonclinical individuals. Scores on the DOCS displayed good performance on indices of reliability and validity, as well as sensitivity to treatment and diagnostic sensitivity, and hold promise as a measure of OC symptoms in clinical and research settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.