全文获取类型
收费全文 | 108篇 |
免费 | 8篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 44篇 |
机械仪表 | 4篇 |
建筑科学 | 11篇 |
能源动力 | 6篇 |
轻工业 | 10篇 |
水利工程 | 2篇 |
无线电 | 9篇 |
一般工业技术 | 13篇 |
冶金工业 | 3篇 |
自动化技术 | 13篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 10篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 12篇 |
2013年 | 9篇 |
2012年 | 7篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 7篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 2篇 |
排序方式: 共有116条查询结果,搜索用时 0 毫秒
21.
Raimundo Barreto Paulo Maciel Eduardo Tavares Romulo Devezas Freitas Meuse Oliveira Ricardo Massa Lima 《Design Automation for Embedded Systems》2008,12(1-2):31-62
Over the last few years, embedded software synthesis has drawn much attention. However, few works deal with software synthesis for hard real-time systems considering arbitrary inter-tasks precedence and exclusion relations. Code generation for meeting all timing and resource constraints is not a trivial task. Thus, this research area has several open issues, mainly related to generation of predictable-guaranteed scheduled code. The method proposed in this paper starts from a high-level specification, and automatically translates such specification into a time Petri net model; this model is adopted for finding a feasible static schedule meeting all constraints. If found, the approach generates a scheduled code, based on the found feasible schedule. Therefore, the user just enter the specification and receives, as result, the scheduled code. Thus, all intermediary phases are hidden from the users. 相似文献
22.
da Silva Paulo F. Santana Ewaldo E. C. Cruz Carlos A. M. Aquino Vivianne S. Castro Luís S. O. Serres Alexandre J. R. Freire Raimundo C. S. Silva Paulo H. F. 《Wireless Personal Communications》2021,119(1):329-341
Wireless Personal Communications - This paper presents the development of a compact monopole antenna bioinspired in the Opuntia ficus-indica plant-shape, generated by Gielis formula, built in... 相似文献
23.
Cover Picture: Stabilization of Telomeric I‐Motif Structures by (2′S)‐2′‐Deoxy‐2′‐C‐Methylcytidine Residues (ChemBioChem 12/2017)
下载免费PDF全文
![点击此处可从《Chembiochem : a European journal of chemical biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
24.
Stabilization of Telomeric I‐Motif Structures by (2′S)‐2′‐Deoxy‐2′‐C‐Methylcytidine Residues
下载免费PDF全文
![点击此处可从《Chembiochem : a European journal of chemical biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Anna Aviñó María Dellafiore Dr. Raimundo Gargallo Prof. Dr. Carlos González Dr. Adolfo M. Iribarren Dr. Javier Montserrat Prof. Dr. Ramon Eritja 《Chembiochem : a European journal of chemical biology》2017,18(12):1123-1128
G‐quadruplexes and i‐motifs are tetraplex structures present in telomeres and the promoter regions of oncogenes. The possibility of producing nanodevices with pH‐sensitive functions has triggered interest in modified oligonucleotides with improved structural properties. We synthesized C‐rich oligonucleotides carrying conformationally restricted (2′S)‐2′‐deoxy‐2′‐C‐methyl‐cytidine units. The effect of this modified nucleoside on the stability of intramolecular i‐motifs from the vertebrate telomere was investigated by UV, CD, and NMR spectroscopy. The replacement of selected positions of the C‐core with C‐modified residues induced the formation of stable intercalated tetraplexes at near‐neutral pH. This study demonstrates the possibility of enhancing the stability of the i‐motif by chemical modification. 相似文献
25.
Ricardo MONTEIRO Miguel ARA JO Raimundo DELGADO M rio MARQUES 《Frontiers of Structural and Civil Engineering》2018,12(1):109
The increasing awareness of the general society toward the seismic safety of structures has led to more restrictive performance requirements hence, many times, to the need of using new and more accurate methods of analysis of structures. Among these, nonlinear static procedures are becoming, evermore, the preferred choice of the majority of design codes, as an alternative to complete nonlinear time-history analysis for seismic design and assessment of structures. The many available software tools should therefore be evaluated and well understood, in order to be easily and soundly employed by the practitioners. The study presented herein intends to contribute to this need by providing further insight with respect to the use of commonly employed structural analysis software tools in nonlinear analysis of bridge structures. A comparison between different nonlinear modeling assumptions is presented, together with the comparison with real experimental results. Furthermore, alternative adaptive pushover procedures are proposed and applied to a case study bridge, based on a generic plastic hinge model. The adopted structural analysis program proved to be accurate, yielding reliable estimates, both in terms of local plastic hinge behavior and global structural behavior. 相似文献
26.
The wetting behavior and detailed surface energetics of a racemate crystalline system were measured via contact angle measurements and inverse gas chromatography at finite concentrations. The advancing contact angles for water, diiodomethane, formamide, and ethylene glycol were measured on specific facets for racemic ibuprofen and S-(+)-ibuprofen single macroscopic crystals, and were found to be facet dependent for both systems. This observation demonstrates that variation in molecular orientation within the crystal lattice results in variations in exposed surface chemistry for differing facets, which results in anisotropic wetting behavior as previously reported. Surface free energy profiles of the ibuprofen racemates determined using a novel inverse gas chromatography method showed that powder samples (75–150 µm particle diameter) exhibited relatively homogeneous surface energies, with similar values of γSV d to those obtained by the contact angle analysis. These results lead us to conclude that ibuprofen exhibited a low level of surface heterogeneity, with the dominant facet of these powders exhibiting a low γSV d, with high energetic sites estimated to be < 3% of exposed available surface. 相似文献
27.
Luciana S. Freire Ermete Antolini Marcelo Linardi Elisabete I. Santiago Raimundo R. Passos 《International Journal of Hydrogen Energy》2014
The effect of operational parameters on the performance of PEMFCs by using serpentine flow field channels with different (rectangular and trapezoidal) cross-section shape has been investigated. More than cell temperature and pressure, reactant humidification temperature (Tha,c) has a significant influence on the effect of serpentine channels with trapezoidal cross-section on cell performance. The high capability of water removal by serpentine channels with trapezoidal cross-section positively affects the fuel cell performance when the water content in the system is high, as in the case of the reactant humidification temperature higher than cell temperature (Tc). On the contrary, when the water content in the cell is low, as in the case of Tha,c = Tc, the high ability of water removal of serpentine channels with trapezoidal cross-section results in a less effective membrane/cathode hydration. Conversely, the effect of Tha,c on the performance of the cell with serpentine channels with rectangular cross-section is negligible. 相似文献
28.
Raimundo Carlos Silverio Freire Adrião Duarte Dória Neto Eve Maria Freire De Aquino 《International Journal of Fatigue》2009,31(5):831-839
The purpose of this paper is to assess the applicability of two artificial neural networks (ANN) architecture, perceptron ANN, modular ANN, and Adam’s equation in the modeling of fatigue failure in polymer composites, more specifically in glass fiber reinforced plastic (GFRP). In the application of the model using ANN we show the feasibility of obtaining good results with a small number of S–N curves. The other model used involves applying empirical equations known as Adam’s equations. A comparative study on the application of the aforementioned models is developed based on statistical tools such as correlation coefficient and mean square error. For this analysis we used composite materials in the form of laminar structures with distinct stacking sequences, which are applied industrially in the construction of large reservoirs. Reinforcements consist of mats and bidirectional textile fabric made of E-glass fibers soaked in unsaturated orthophthalic polyester resin. These were tested for six different stress ratios: R = 1.43, 10, ?1.57, ?1, 0.1, and 0.7. The results showed that although ANN modeling is in the initial phase, it has great application potential. 相似文献
29.
The performance of a proton exchange membrane fuel cell (PEMFC) with gas diffusion cathodes having the catalyst layer applied directly onto Nafion membranes is investigated with the aim at characterizing the effects of the Nafion content, the catalyst loading in the electrode and also of the membrane thickness and gases pressures. At high current densities the best fuel cell performance was found for the electrode with 0.35 mg Nafion cm−2 (15 wt.%), while at low current densities the cell performance is better for higher Nafion contents. It is also observed that a decrease of the usual Pt loading in the catalyst layer from 0.4 to ca. 0.1 mg Pt cm−2 is possible, without introducing serious problems to the fuel cell performance. A decrease of the membrane thickness favors the fuel cell performance at all ranges of current densities. When pure oxygen is supplied to the cathode and for the thinner membranes there is a positive effect of the increase of the O2 pressure, which raises the fuel cell current densities to very high values (>4.0A cm−2, for Nafion 112—50 μm). This trend is not apparent for thicker membranes, for which there is a negligible effect of pressure at high current densities. For H2/air PEMFCs, the positive effect of pressure is seen even for thick membranes. 相似文献
30.