全文获取类型
收费全文 | 323篇 |
免费 | 25篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
综合类 | 3篇 |
化学工业 | 84篇 |
金属工艺 | 3篇 |
机械仪表 | 20篇 |
建筑科学 | 7篇 |
能源动力 | 12篇 |
轻工业 | 61篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 43篇 |
一般工业技术 | 60篇 |
冶金工业 | 14篇 |
自动化技术 | 31篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 14篇 |
2021年 | 20篇 |
2020年 | 14篇 |
2019年 | 13篇 |
2018年 | 22篇 |
2017年 | 11篇 |
2016年 | 21篇 |
2015年 | 10篇 |
2014年 | 10篇 |
2013年 | 36篇 |
2012年 | 14篇 |
2011年 | 22篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 14篇 |
2007年 | 14篇 |
2006年 | 14篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有349条查询结果,搜索用时 0 毫秒
21.
Mokhtar Guissous Yveline Le Dréau Hasna Boulkhroune Toufik Madani Jacques Artaud 《Journal of the American Oil Chemists' Society》2018,95(3):267-281
Differences in triacylglycerol, fatty acid, squalene, and tocopherol compositions were demonstrated between 8 varieties of virgin olive oils (Aberkane, Aguenaou, Aharoun, Aimel, Bouchouk Guergour, Bouichret, Chemlal, and Sigoise) from Petite Kabylie area, north eastern Algeria. Fatty acid and triacylglycerol morphotypes characterized each variety. A principal component analysis, based on triacylglycerol, fatty acid, and squalene compositions, differentiates between varieties. Minor fatty acids and squalene, usually not taken into account individually in authentication studies, are strongly involved in this differentiation, whereas the discriminant power of tocopherols is weak. Soft Independent Modeling of Class Analogy classification using chemical compositions as variables showed a high potential to authenticate the varietal origin of Algerian virgin olive oils. 相似文献
22.
23.
24.
Samia Dabbou Faten Brahmi Ameni Taamali Manel Issaoui Youssef Ouni Mohamed Braham Mokhtar Zarrouk Mohamed Hammami 《Journal of the American Oil Chemists' Society》2010,87(10):1199-1209
The effects of the contents of lipids, pigments, α-tocopherol and phenols were studied in relation to the antioxidant capacity
of five virgin olive oils obtained from five olive cultivars planted in Tunisia (Arbequina, Koroneiki, Leccino, Oueslati and
Chemchali). The antioxidant capacities were evaluated by two different radical scavenging activities: radical scavenging activity
by the DPPH assay (RSA-DPPH) and total antioxidant status by the ABTS test (TAA-ABTS). The highest contents of antioxidant
compounds (75.96, 10.34, 6.32, 15.39 and 241.52 mg kg−1 for oleic acid, O/L ratio, carotenes, chlorophylls and total phenols, respectively) were found for the Koroneiki cultivar
except for α-tocopherol and o-diphenols, which had the highest contents (369 and 160.7 mg kg−1, respectively) in the Leccino and Chemchali cultivars (cvs). Furthermore, the highest antioxidant capacity in virgin olive
oil was observed in the Koroneiki cultivar (0.24 mmol TE kg−1) followed by the Chemchali and Leccino cvs (0.22 and 0.13 mmol TE kg−1) for the TAA-ABTS test. However, the RSA-DPPH activity was higher for the Chemchali cultivar (19.9%) than for the Koroneiki
and Leccino cvs (18.4 and 13.5%, respectively). Correlation between these capacities and the oil composition revealed that
they were mainly influenced by the carotene content, followed by chlorophyll and phenolic contents where the ABTS test was
more pronounced. Then, the antioxidant capacity of the virgin olive oils was correlated with polar components and the lipid
profile which are important for its shelf life. 相似文献
25.
The aim of this research is to characterize the organic matter showing endotoxicity in domestic wastewater. It is assumed that endotoxicity is caused by lipo-polysaccharide (LPS), particularly large and hydrophobic molecules. In this study, a batch experiment (decay test for 12 h) was conducted to confirm whether LPS is the cause of endotoxicity or not. 2-keto-3deoxyoctulosonic acid (KDO) was used as an indicator of presence of LPS.A size and structural characterization of several samples from raw and domestic wastewater was also carried out in order know which fractions are causing endotoxicity. Endotoxin and KDO patterns were found to be similar, peaking at the same time. Thus, organic matter showing endotoxicity, such as LPS was released in the decay test. Moreover, the organic matter released from bacteria during decay test was partly biodegradable. Results from size characterization (Molecular Weight Distribution) showed that the majority of endotoxin (up to 82%), in domestic sewage and secondary effluents,is composed of molecules larger than 100 kDa and less than 0.1 μm. Similarly, structural characterization (hydrophobic and hydrophilic) showed that the majority of endotoxin, ranging from 59% to 83% of the total endotoxicity, is hydrophobic fractions. Therefore, removing large and hydrophobic molecules from wastewater can be an effective way to achieve a significant decrease in its endotoxicity. 相似文献
26.
Ahmed Mokhtar 《Canadian Metallurgical Quarterly》2000,6(3):91-94
Illinois Institute of Technology started a bachelor of science degree program in architectural engineering in the fall of 1995. The program's curriculum requires the students to take 136 semester credit hours during a period of eight semesters, with the option for specialization in one of the three main areas of architectural engineering. To share the experience worldwide with schools that intend to offer similar bachelor degrees, this paper presents the architectural engineering curriculum at Illinois Institute of Technology. It discusses the objectives of the curriculum, the constraints upon its structure, as well as the challenges that face the establishment of an architectural engineering program. 相似文献
27.
Michael Buric Kevin P. Chen Matrika Bhattarai Philip R. Swinehart Mokhtar Maklad 《Photonics Technology Letters, IEEE》2007,19(5):255-257
The use of liquid hydrogen as a fuel requires low-cost multipoint sensing of hydrogen gas for leak detection and location well below the 4% explosion limit of hydrogen. Herein is presented a multipoint in-fiber hydrogen sensor capable of hydrogen detection below 0.5% concentration with a response time of less than 10 s. Our solution entails use of a fiber Bragg grating (FBG) coated with a layer of hydrogen-absorbing palladium which, in turn, induces strain in the FBG in the presence of hydrogen. Infrared power laser light is used to induce heating in the palladium coating which dramatically decreases sensor response time and increases the sensor's sensitivity at low temperatures. This technology promises an inexpensive fiber solution for a multipoint hydrogen detection array with only one fiber feed-through 相似文献
28.
ABSTRACTThis paper deals with partial information stochastic optimal control problem for general controlled mean-field systems driven by Teugels martingales associated with some Lévy process having moments of all orders, and an independent Brownian motion. The coefficients of the system depend on the state of the solution process as well as of its probability law and the control variable. We establish a set of necessary conditions in the form of Pontryagin maximum principle for the optimal control. We also give additional conditions, under which the necessary optimality conditions turn out to be sufficient. The proof of our result is based on the derivative with respect to the probability law by applying Lions derivatives and a corresponding Itô formula. As an application, conditional mean-variance portfolio selection problem in incomplete market, where the system is governed by some Gamma process is studied to illustrate our theoretical results. 相似文献
29.
Due to their advantages, facial recognition systems are among the most widely used biometric systems in recent years. However, their drawback is that they can easily be deceived by using 3D masks, which are replicas of real faces. To confirm this fact, we have tested the vulnerability to 3D masks attacks of the already approved Legendre moments invariants (LMI)-based face recognition method. This has been achieved by using the 3D mask attack database (3DMAD), which consists of real faces and faces with 3D masks. The obtained spoof false acceptance rate (SFAR) was close to 65%, which proves that this recognition system is vulnerable to 3D masks attacks. This is generally the case of other face recognition systems, with no anti-spoofing provision. In this paper, a face recognition method is proposed to prevent hackers from deceiving face recognition systems by using 3D masks of people belonging to the system database. This method combines the LMI and the linear discriminant analysis for characteristic features extraction, and the maximum likelihood for classification. With a 97.6% recognition rate and a SFAR equal to 0.83%, the results obtained may be considered as very satisfactory. These results, while obtained with a lower computational time, compare favorably with those of the state-of-the-art method that uses the same 3DMAD database. 相似文献
30.
Arab Mustapha Amine Zemri Mokhtar Blaoui Mohamed Mossaab 《Journal of Failure Analysis and Prevention》2018,18(6):1625-1630
Journal of Failure Analysis and Prevention - In this study, the effect of tool rotational speed on mechanical properties of AA 6082-T6 aluminum alloy was investigated. Different welded joints were... 相似文献