全文获取类型
收费全文 | 247篇 |
免费 | 17篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 40篇 |
金属工艺 | 12篇 |
机械仪表 | 2篇 |
建筑科学 | 6篇 |
能源动力 | 12篇 |
轻工业 | 51篇 |
水利工程 | 1篇 |
无线电 | 13篇 |
一般工业技术 | 30篇 |
冶金工业 | 45篇 |
原子能技术 | 2篇 |
自动化技术 | 47篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 12篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 11篇 |
2013年 | 13篇 |
2012年 | 16篇 |
2011年 | 13篇 |
2010年 | 17篇 |
2009年 | 16篇 |
2008年 | 10篇 |
2007年 | 15篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 16篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 4篇 |
排序方式: 共有264条查询结果,搜索用时 18 毫秒
1.
2.
Hector Archila Sebastian Kaminski David Trujillo Edwin Zea Escamilla Kent A. Harries 《Materials and Structures》2018,51(4):102
The use of small diameter whole-culm (bars) and/or split bamboo (a.k.a. splints or round strips) has often been proposed as an alternative to relatively expensive reinforcing steel in reinforced concrete. The motivation for such replacement is typically cost—bamboo is readily available in many tropical and sub-tropical locations, whereas steel reinforcement is relatively more expensive—and more recently, the drive to find more sustainable alternatives in the construction industry. This review addresses such ‘bamboo-reinforced concrete’ and assesses its structural and environmental performance as an alternative to steel reinforced concrete. A prototype three bay portal frame, that would not be uncommon in regions of the world where bamboo-reinforced concrete may be considered, is used to illustrate bamboo reinforced concrete design and as a basis for a life cycle assessment of the same. The authors conclude that, although bamboo is a material with extraordinary mechanical properties, its use in bamboo-reinforced concrete is an ill-considered concept, having significant durability, strength and stiffness issues, and does not meet the environmentally friendly credentials often attributed to it. 相似文献
3.
Leonardo Trujillo 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2011,15(8):1551-1567
Genetic programming (GP) is one of the most widely used paradigms of evolutionary computation due to its ability to automatically
synthesize computer programs and mathematical expressions. However, because GP uses a variable length representation, the
individuals within the evolving population tend to grow rapidly without a corresponding return in fitness improvement, a phenomenon
known as bloat. In this paper, we present a simple bloat control strategy for standard tree-based GP that achieves a one order
of magnitude reduction in bloat when compared with standard GP on benchmark tests, and practically eliminates bloat on two
real-world problems. Our proposal is to substitute standard subtree crossover with the one-point crossover (OPX) developed
by Poli and Langdon (Second online world conference on soft computing in engineering design and manufacturing, Springer, Berlin
(1997)), while maintaining all other GP aspects standard, particularly subtree mutation. OPX was proposed for theoretical purposes
related to GP schema theorems, however since it curtails exploration during the search it has never achieved widespread use.
In our results, on the other hand, we are able to show that OPX can indeed perform an effective search if it is coupled with
subtree mutation, thus combining the bloat control capabilities of OPX with the exploration provided by standard mutation. 相似文献
4.
In areas where tap water has a high salt content, wastewater is not appropriate for reuse in agriculture, particularly for sensitive crops. One alternative is reduction, via desalination, of the brackish character to the secondary effluent. A filtration stage is also required before desalination. On the other hand, used reverse osmosis membranes can be recycled and used as filters in the advanced treatment stage in order to reduce suspended matter contained in the secondary effluent—one advantage being the environmental recovery of solid waste. Used membranes can be treated with strong chemical oxidants to peel off the active separation layer in order to transform them into microfiltration or ultrafiltration elements. Preliminary tests have been carried out with 8″ elements, aimed at comparing membrane performance before and after the peeling process. An index denoted as peeling effectiveness (high flux, high salt passage) is used for comparison. It was soon observed that potassium permanganate was more effective than others, together with sodium hydroxide. Doses around 1000 mg/L KMnO4 provided the best results. It was also concluded that membrane cleaning, done with sodium bisulphite prior to peeling, was better when recirculating the cleaning solution around the membrane rather than soaking it. Next steps in the research will test the actual filtration capability of the peeled membranes in actual wastewater. 相似文献
5.
The complexity of the data warehouse (DW) development process requires to follow a methodological approach in order to be successful. A widely accepted approach for this development is the hybrid one, in which requirements and data sources must be accommodated to a new DW model. The main problem is that we lose the relationships between requirements, elements in the multidimensional (MD) conceptual models and data sources in the process, since no traceability is explicitly specified. Therefore, this hurts requirements validation capability and increases the complexity of Extraction, Transformation and Loading processes. In this paper, we propose a novel trace metamodel for DWs and focus on the relationships between requirements and MD conceptual models. We propose a set of Query/View/Transformation rules to include traceability in DWs in an automatic way, allowing us to obtain a MD conceptual model of the DW, as well as a trace model. Therefore, we are able to trace every requirement to the MD elements, further increasing user satisfaction. Finally, we show the implementation in our Lucentia BI tool. 相似文献
6.
R. Trujillo J. Mou P. E. Phelan D. S. Chau 《The International Journal of Advanced Manufacturing Technology》2004,23(3-4):176-182
Abstact This paper presents an investigation of the use of electrostrictive silicone polymers as actuators for mesoscale devices. The generated strains of both flat and rolled actuators, based on Dow Corning Sylgard 182 and 184, with sputtered gold electrodes, are presented as functions of the applied electric field. Variables examined in this study include silicone film thickness, gold electrode thickness, cycling of the applied electric field, and actuator configuration (flat or rolled). In general, thinner silicone films and gold electrodes yielded greater strains, at a constant applied field. The actuator performance tended to deteriorate with repeated application of the electric field, and the gold electrodes cracked after being subjected to a large percentage strain.Nomenclature
A
Cross sectional area, mm2
-
a
1
, a
2
electrostrictive constants, m2/V2
-
D
diameter, mm
-
E
electric field, V/m
-
o
permittivity of free space, F/m
-
dielectric constant for silicones, F/m
-
F
force, N
-
J
work, J
-
l
length, m
-
S
ij
strain tensor, dimensionless
-
S
ijkl
tensor of elastic compliance coefficients, m
-
t
thickness, m
-
T
kl
stress tensor, Pa
-
u
i
displacement vector, mm
-
V
volume, mm3
-
Poisson ratio, dimensionless
-
w
width, m
-
Y
Youngs modulus, Pa 相似文献
7.
J.P. Escobedo E.K. Cerreta C.P. Trujillo D.T. Martinez R.A. Lebensohn V.A. Webster G.T. Gray 《Acta Materialia》2012,60(11):4379-4392
Experiments were conducted to characterize the influence of texture and impact velocity on the dynamic, high-strain, tensile extrusion of zirconium. Bullet-shaped samples were machined from a clock-rolled, highly textured Zr plate. Specimens in two orthogonal directions were tested: the extrusion direction aligned with either the in-plane (IP) rolling or the through-thickness (TT) direction of the plate. The post-extrusion microstructure and texture evolution were examined using electron backscatter diffraction microscopy and modeled using the viscoplastic self-consistent model. It was found that extrusion deformation was accomplished through a combination of twinning and slip with their relative activity greatly depending on the initial texture. In this regard, higher elongations in the IP samples as compared to the TT samples were observed at similar test velocities. This difference in ductility is discussed in terms of the material’s ability to accommodate plastic deformation. Due to the availability of a larger number of slip systems with relatively high Schmid factors in the IP samples under this configuration, plastic deformation by prismatic slip can be easily achieved, resulting in larger elongations. On the contrary, for TT samples, twinning preceded deformation by slip. This sequential deformation process, driven by the need to reorient the microstructure favorably to slip, led to diminished elongations to failure. 相似文献
8.
Juan P. Escobedo Ellen K. Cerreta Daniel T. Martinez Carl P. Trujillo Ricardo A. Lebensohn George T. Gray III 《Metallurgical and Materials Transactions A》2014,45(13):5877-5882
The influence of temperature on the dynamic tensile behavior of Zr has been investigated. Bullet-shaped Zr samples with two different textures were dynamically extruded at room temperature and 523 K (250 °C). A higher ductility was measured for samples deformed at elevated temperature as compared to those extruded at room temperature. This difference in ductility is discussed in terms of zirconium’s ability to accommodate plastic deformation via thermally enhanced slip activity, as evidenced by examination of the deformed microstructures. 相似文献
9.
Buzzi Maria Claudia Buzzi Marina Leporini Barbara Trujillo Amaury 《Multimedia Tools and Applications》2017,76(4):5141-5169
Multimedia Tools and Applications - We present an analysis of how visually impaired people perform gestures on touch-screen smartphones and report their preferences, explaining the procedure and... 相似文献
10.
Leon Cohen Elsa Sanchez Mariluz Martin Fernando Soto Francisco Trujillo 《Journal of surfactants and detergents》2016,19(5):1089-1092
The effects of both linear alkylbenzene sulfonate (LAS) and zein protein concentrations on protein solubilization were investigated to better understand the influence of increasing concentration of the surfactant on protein denaturation and skin irritation. Different methods have been used for the determination of the amount of protein dissolved. A wide range of LAS concentrations and zein amounts were used. The results confirm that protein solubilization increases with LAS concentration increase and demonstrate that a minimum LAS/Zein ratio exists for all the zein to be dissolved. 相似文献