全文获取类型
收费全文 | 137篇 |
免费 | 3篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 16篇 |
机械仪表 | 3篇 |
建筑科学 | 1篇 |
能源动力 | 10篇 |
轻工业 | 16篇 |
水利工程 | 3篇 |
无线电 | 27篇 |
一般工业技术 | 28篇 |
冶金工业 | 4篇 |
自动化技术 | 30篇 |
出版年
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 8篇 |
2013年 | 12篇 |
2012年 | 4篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 7篇 |
2008年 | 12篇 |
2007年 | 11篇 |
2006年 | 3篇 |
2005年 | 12篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 2篇 |
1999年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1990年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有140条查询结果,搜索用时 15 毫秒
21.
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 has been recognized as a major foodborne pathogen responsible for frequent gastroenteritis outbreaks. Phages and essential oils can be used as a natural antimicrobial method to reduce bacterial pathogens from the food supply. The objective of this study was to determine the effect of a bacteriophage cocktail, BEC8, alone and in combination with the essential oil trans-cinnameldehyde (TC) on the viability of a mixture of EHEC O157:H7 strains applied on whole baby romaine lettuce and baby spinach leaves. The EHEC O157:H7 strains used were NalR mutants of EK27, ATCC 43895, and 472. Exponentially growing cells from tryptic soy (TS) broth cultures were spot inoculated on leaves and dried. EHEC cells were placed at low, medium, and high inoculum levels (104, 105, and 106 CFU/mL, respectively). Appropriate controls, BEC8 (approx. 106 PFU/leaf), and TC (0.5% v/v) were applied on treated leaves. The leaves were incubated at 4, 8, 23, and 37 °C in Petri dishes with moistened filter papers. EHEC survival was determined using standard plate count on nalidixic acid (50 μg/mL) Sorbitol MacConkey agar. No survivors were detected when both leaves were treated with BEC8 or TC individually at low inoculum levels after 24 h at 23 and 37 °C. When the EHEC inoculum size increased and/or incubation temperature decreased, the efficacy of BEC8 and TC decreased. However, when the two treatments were combined, no survivors were detected after 10 min at all temperatures and inoculum levels on both leafy greens. These results indicated that the BEC8/TC combination was highly effective against EHEC on both leafy greens. This combination could potentially be used as an antimicrobial to inactivate EHEC O157:H7 and reduce their incidence in the food chain. 相似文献
22.
23.
The aim of this article is the assessment of low-carbon energy technologies in Europe against a set of sustainability and resilience criteria. The assessment was based on a survey that was conducted among 40 European experts. Solar Photovoltaic was the technology that proved to achieve high performance against many criteria, whereas nuclear was assessed by the experts with relatively low performance against most of the criteria. Furthermore, it became evident that there is high degree of convergence between the experts, and therefore high degree of confidence, on specific aspects such as the high level of public resistance against Nuclear and the low stability of energy generation of wind onshore. The experts had major disagreements on the performance of carbon capture and storage (CCS) technologies against technological maturity and innovative ability criteria, which reveals a high degree of uncertainty on how CCS will be deployed in the future, pointing out a direction for future research. 相似文献
24.
25.
Jens A. Hauch Pavel Schilinsky Stelios A. Choulis Richard Childers Markus Biele Christoph J. Brabec 《Solar Energy Materials & Solar Cells》2008,92(7):727-731
Flexible organic solar cells and modules based on P3ht:PCBM bulk-heterojunctions were fabricated and their lifetime was investigated under laboratory and outdoor conditions. In the laboratory cells were exposed to 1 sun illumination at 65 °C in order to accelerate the degradation. The outdoor behavior of modules was investigated at the Konarka rooftop testing setup in Lowell, MA (USA). We show that these flexible polymer solar cells have a good light stability, passing 1000 h under accelerated light soaking conditions in the laboratory, and that flexible modules survived over 1 year of outdoor exposure without performance losses. 相似文献
26.
Naoto Sakakibara Stelios Kyriakides Edmundo Corona 《International Journal of Mechanical Sciences》2008,(12):1586-1597
This paper is concerned with the effect of internal corrosion or erosion defects on the collapse of pipelines under external pressure. Experiments are conducted on SS-304 tubes with D/t's of 21.0 and 18.7 with axially uniform grooves of several thicknesses and angular spans of 6–60°. All specimens exhibited the classical ovalization mode of collapse with the grooved side being more deformed. For groove angles between 6° and 20° the collapse pressure decreases as the angle increases but remains essentially constant for angles between 20° and 60°. The collapse pressure was found to decrease with groove depth, reducing by nearly 50% when the groove depth reached 50% of the pipe wall thickness. The experiments were simulated numerically using both the custom computer code BEPTICO as well as an axially uniform finite element model. The predictions were found to follow closely the trends of the experimental results. The three dimensionality of grooves was examined using appropriate finite element models. It was found that grooves shorter than about 8D constitute local imperfections and accurate prediction of their effect on collapse pressure requires fully 3-D modeling. By contrast, grooves 10D long or longer behave essentially as “long” grooves and can be analyzed using 2-D models. 相似文献
27.
Anastasia Houndri Stelios Polymenis Yannis Chryssoulakis Dimitris Pantelis 《Metallurgical and Materials Transactions A》1992,23(6):1801-1806
Microstructure improvements of a nickel electrodeposited Al−Si alloy were studied after high-power laser melting treatment
through a single pass or partially overlapping successive adjacent passes. In some cases, laser melting treatment was preceded
by a 5-hour heating of the specimens at 500°C in argon atmosphere furnace. Microstructure observations and microhardness measurements
were carried out on the specimens before and after laser melting treatment with and without preheating. Best results concerning
microhardness, microstructural homogeneity, and porosity elimination, as well as adhesion of the nickel coating on the Al−Si
alloy, were achieved when the specimens were first subjected to heating at 500°C in an argon atmosphere furnace for 5 hours
and then submitted to a laser melting treatment through successive adjacent laser passes with an overlapping rate of 70 pct.
Microstructure studies were carried out employing X-ray diffraction analysis (XRD) and energy-dispersive spectrometry (EDS).
AlNi and Al3Ni phases were detected in the diffusion area which resulted from the 5-hour heating. AlNi, Al3Ni, and Al3Ni2 phases were identified in the laser melted zones (LMZs). Each one of the above phase was found to be the main phase under
different conditions. 相似文献
28.
The aim of this study is to establish the meteorological basis for the assessment of wind energy resources in Cyprus and to provide suitable data for evaluating the potential wind power. For this purpose the mean values, the systematic daily and annual variations, the frequency distributions and the estimation of the extreme values are determined. Predictions were also obtained from the WAsP model and, finally, the Wind Atlas of the island, in the form of contours of constant wind speed, was produced. 相似文献
29.
Kirill Mikhaylov Stelios Rigopoulos George Papadakis 《American Institute of Chemical Engineers》2021,67(10):e17348
We combine reduced order modeling and system identification to reconstruct the temporal evolution of large-scale vortical structures behind the blades of a Rushton impeller. We performed direct numerical simulations at Reynolds number 600 and employed proper orthogonal decomposition (POD) to extract the dominant modes and their temporal coefficients. We then applied the identification algorithm, N4SID, to construct an estimator that captures the relation between the velocity signals at sensor points (input) and the POD coefficients (output). We show that the first pair of modes can be very well reconstructed using the velocity time signal from even a single sensor point. A larger number of points improves accuracy and robustness and also leads to better reconstruction for the second pair of POD modes. Application of the estimator derived at Re = 600 to the flows at Re = 500 and 700 shows that it is robust with respect to changes in operating conditions. 相似文献
30.