全文获取类型
收费全文 | 348篇 |
免费 | 13篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 68篇 |
金属工艺 | 9篇 |
机械仪表 | 14篇 |
建筑科学 | 5篇 |
能源动力 | 35篇 |
轻工业 | 35篇 |
石油天然气 | 1篇 |
无线电 | 34篇 |
一般工业技术 | 58篇 |
冶金工业 | 29篇 |
原子能技术 | 6篇 |
自动化技术 | 69篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 23篇 |
2020年 | 18篇 |
2019年 | 18篇 |
2018年 | 15篇 |
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 18篇 |
2014年 | 21篇 |
2013年 | 30篇 |
2012年 | 21篇 |
2011年 | 28篇 |
2010年 | 17篇 |
2009年 | 16篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 9篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1976年 | 2篇 |
排序方式: 共有368条查询结果,搜索用时 281 毫秒
11.
Djamel Bouchaffra Author Vitae 《Pattern recognition》2010,43(7):2590-2607
Current extensions of hidden Markov models such as structural, hierarchical, coupled, and others have the power to classify complex and highly organized patterns. However, one of their major limitations is the inability to cope with topology: When applied to a visible observation (VO) sequence, the traditional HMM-based techniques have difficulty predicting the n-dimensional shape formed by the symbols of the VO sequence. To fulfill this need, we propose a novel paradigm named “topological hidden Markov models” (THMMs) that classifies VO sequences by embedding the nodes of an HMM state transition graph in a Euclidean space. This is achieved by modeling the noise embedded in the shape generated by the VO sequence. We cover the first and second level topological HMMs. We describe five basic problems that are assigned to a second level topological hidden Markov model: (1) sequence probability evaluation, (2) statistical decoding, (3) structural decoding, (4) topological decoding, and (5) learning. To show the significance of this research, we have applied the concept of THMMs to: (i) predict the ASCII class assigned to a handwritten numeral, and (ii) map protein primary structures to their 3D folds. The results show that the second level THMMs outperform the SHMMs and the multi-class SVM classifiers significantly. 相似文献
12.
Rafael Antonello Stênio Fernandes Josilene Moreira Paulo Cunha Carlos Kamienski Djamel Sadok 《Multimedia Systems》2009,15(1):33-47
Virtual Worlds (VW), such as Massive Multiplayer Online Social Games, have been gaining increasing attention in the last few
years, mainly due to the new way users interact with them. However, little effort has been devoted to understand their traffic
profile and the implications to the traffic management area. With the current growing rate of VWs’ usage, their traffic demand
could eventually impose a significant burden on the operation of a typical Internet Service Provider (ISP) network. In this
paper, we seek to understand the traffic behavior of an increasingly popular VW application, namely Second Life (SL), from
both the connection and network level perspectives. We also show results of a traffic analysis of a SL client, when an avatar
performs different actions in the VW, at different places and under different network conditions. Our results show that SL
makes intensive use of network resources (mostly bandwidth), since the capacity needed for having a full SL experience (listening
to live music) may reach 500 kbps. We then extend the traffic analysis work on SL by providing analytical models for its traffic
profile. We aim at helping the network management and planning area to estimate the impact of an intense use of such VW on
access links or core networks. Such synthetic models are also useful to the networking research community for the use in network
simulations. 相似文献
13.
Mohammed Aider Djamel Djenane Wassef B. Ounis 《International Journal of Food Science & Technology》2012,47(5):1028-1036
Amino acid composition, protein hydrophobicity, foaming and emulsifying properties of mustard protein isolate at pH 3, 5, 7 and in 0.05 and 0.1 m NaCl were studied. Glutamic (19.18 ± 0.30%) and aspartic (7.49 ± 0.11%) acids were the dominants. Foaming ability was enhanced by NaCl. Time to reach 75 mL foam was 23% higher in water than in NaCl. Drained volume after 10 min was concentration dependent and was the lowest in 0.05 and 0.1 m NaCl at protein concentration of 2.5% and 5%. The emulsifying properties were pH and concentration dependent, and the best results were obtained at pH 3, corresponding to the highest positive charge density of the protein surface. The highest emulsion stability (90.22 ± 3.52%) was obtained in 0.05 m NaCl and 5% protein concentration, whereas the lowest (63.00 ± 1.06%) was in water at all protein concentrations. Protein hydrophobicity was low and depended of pH but not of NaCl. 相似文献
14.
15.
In this research, the effect of NbF5 as an additive on the hydrogen desorption kinetics of MgH2 was investigated and compared to TiH2, Mg2Ni and Nb2O5 catalysts. The kinetics measurements were done using a method in which the ratio of the equilibrium plateau pressure to the opposing pressure was the same for all the reactions. The data showed NbF5 to be vastly superior to the other catalysts for improving the desorption kinetics of MgH2. The rates of desorption were found to be in the order NbF5 ? Nb2O5 > Mg2Ni > TiH2 > Pure MgH2. Kinetic modeling measurements showed that chemical reaction at the phase boundary to be the likely process controlling the reaction rates. TPD analyses showed the mixture with NbF5 has the lowest desorption temperature although it was accompanied with some weight penalty. 相似文献
16.
Abouelkacem Qaiss Hassan Saidi Omar Fassi‐Fehri Mosto Bousmina 《Polymer Engineering and Science》2012,52(12):2637-2644
Cellular polypropylene‐calcium carbonate based piezoelectric films were obtained using biaxial stretching and gas‐mediated inflation followed by a corona discharge treatment using home‐made devices. The obtained results revealed a cellular structure that develops at the interface between the solid particles and the polymer matrix and the final piezoelectric coefficient was found to depend both on the gas pressure profile and on time. The inflation step gives better results when the gas pressure is increased in stepwise manner allowing the gas to adequately intrude the cavities and maintain the required pressure. The overall results are discussed in terms of processing conditions and in terms of the developed microstructure. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers 相似文献
17.
Azim Ziyaei Halimehjani M. Ali Alaei Farzaneh Soleymani Movahed Negin Jomeh Mohammad R. Saidi 《Journal of Sulfur Chemistry》2016,37(5):529-536
An effective approach for the synthesis of 2-(alkylthio)thiazol-4(5H)-ones from alkyl dithiocarbamates and chloroacetyl chloride in the presence of NaHCO3 has been developed. Good to excellent yields of products, simple reaction conditions and general applicability are the most important advantages of this protocol. 相似文献
18.
Propane dehydrogenation on a commercial Pt-Sn/Al2O3 catalyst in a Pd-Ag membrane reactor is considered. A mathematical model is developed to evaluate the performance of the catalytic membrane reactor for the process of propane dehydrogenation. Design and operating conditions are systematically evaluated for key performance metrics such as propane conversion, propylene selectivity, hydrogen selectivity, and hydrogen recovery under different operating conditions. The results confirm that the high performance of the membrane reactor is related to the continuous removal of hydrogen from the reaction zone to shift the reaction equilibrium towards the formation of more propylene and hydrogen. 相似文献
19.
Prof. Roberta Marchetti Ferran Nieto Fabregat Dr. Mateusz Pallach Dr. Djamel Gully Dr. Eric Giraud Prof. Antonio Molinaro Dr. Katarzyna A. Duda Alba Silipo 《Chembiochem : a European journal of chemical biology》2021,22(1):147-150
Acetobacter pasteurianus, a member of the Alphaproteobacteria, is an acetic acid-producing bacterium present on sugar-rich substrates such as such as fruits, flowers and vegetables and traditionally used in the production of fermented food. The preferred living habitat associated with acid conditions makes the structure of the bacterial cell wall interesting to study, due to expected uncommon features. We have used a combination of chemical, analytical and NMR spectroscopy approaches to define the complete structure of the core oligosaccharide from A. pasteurianus CIP103108 LPS. Interestingly, the core oligosaccharide displays a high concentration of negatively charged groups, structural features that might contribute to reinforcing the bacterial membrane. 相似文献
20.
Ali Hemmatifar Mohammad Said Saidi Arman Sadeghi Mahdi Sani 《Microfluidics and nanofluidics》2013,14(1-2):265-276
Dielectrophoresis (DEP) is an electrokinetic phenomenon which is used for manipulating micro- and nanoparticles in micron-sized devices with high sensitivity. In recent years, electrode-based DEP by patterning narrow oblique electrodes in microchannels has been used for particle manipulation. In this theoretic study, a microchannel with triangular electrodes is presented and a detailed comparison with oblique electrodes is made. For each shape, the behavior of particles is compared for three different configurations of applied voltages. Electric field, resultant DEP force, and particle trajectories for configurations are computed by means of Rayan native code. The separation efficiency of the two systems is assessed and compared afterward. The results demonstrate higher lateral DEP force, responsible for particle separation, distributed wider across the channel width for triangular shape electrodes in comparison with the oblique ones. The proposed electrode shape also shows the ability of particle separation by attracting negative DEP particles to or propelling them from the flow centerline, according to the configuration of applied voltages. A major deficiency of the oblique electrodes, which is the streamwise variation of the lateral DEP force direction near the electrodes, is also eliminated in the proposed electrode shape. In addition, with a proper voltages configuration, the triangular electrodes require lower voltages for particle focusing in comparison with the oblique ones. 相似文献