全文获取类型
收费全文 | 894篇 |
免费 | 65篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 10篇 |
综合类 | 2篇 |
化学工业 | 134篇 |
金属工艺 | 6篇 |
机械仪表 | 25篇 |
建筑科学 | 27篇 |
能源动力 | 39篇 |
轻工业 | 63篇 |
水利工程 | 6篇 |
石油天然气 | 4篇 |
无线电 | 227篇 |
一般工业技术 | 192篇 |
冶金工业 | 130篇 |
原子能技术 | 1篇 |
自动化技术 | 96篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 23篇 |
2020年 | 20篇 |
2019年 | 20篇 |
2018年 | 22篇 |
2017年 | 26篇 |
2016年 | 38篇 |
2015年 | 26篇 |
2014年 | 29篇 |
2013年 | 61篇 |
2012年 | 44篇 |
2011年 | 50篇 |
2010年 | 45篇 |
2009年 | 31篇 |
2008年 | 43篇 |
2007年 | 40篇 |
2006年 | 54篇 |
2005年 | 26篇 |
2004年 | 31篇 |
2003年 | 32篇 |
2002年 | 43篇 |
2001年 | 23篇 |
2000年 | 9篇 |
1999年 | 25篇 |
1998年 | 46篇 |
1997年 | 36篇 |
1996年 | 12篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 12篇 |
1992年 | 4篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 1篇 |
排序方式: 共有962条查询结果,搜索用时 15 毫秒
21.
22.
J. C. Leong L. C. Tsao C. J. Fang C. P. Chu 《Journal of Materials Science: Materials in Electronics》2011,22(9):1443-1449
The effects of nano-TiO2 particles on the interfacial microstructures and bonding strength of Sn3.5Ag0.5Cu composite solder joints in ball grid array packages with immersion Sn surface finishes have been investigated. Metallography reveals that addition of nano-TiO2 particle retarded wicker-Cu6Sn5 IMC formed in the Sn3.5Ag0.5Cu composite solder joints. The thickness of the interfacial intermetallic compounds of the solder joint was reduced with increased additions of nano-TiO2 particles (0.25–1.0 wt%), but further additions up to 1.25 wt% decreased the beneficial influence. This indicates that the presence of a small amount of nano-TiO2 particles is effective in suppressing the growth of the intermetallic compounds layer. In addition, the shear strength of the soldered joints was improved by larger nano-TiO2 particle additions, with the peak shear strength occurring at 1.0 wt% of nano-TiO2 particles into the Sn3.5Ag0.5Cu solder. The fracture mode also changed with increased amounts of nano-TiO2 particles. 相似文献
23.
J. Sch?nenberger T. Momose B. Wagner W. H. Leong V. R. Tarnawski 《International Journal of Thermophysics》2012,33(2):342-362
Forty Canadian soils were laboratory tested for the presence of quartz and other minerals using X-ray diffraction/X-ray fluorescence techniques. On average, the highest quartz content was observed in soil samples from sites in Nova Scotia followed by Prince Edward Island sites, whereas soil sample from British Columbia sites had the lowest quartz content. The second most abundant mineral was albite that mainly occurred in soil samples from Ontario and Quebec sites. Illite was the third most abundant and prevailed in soils mainly from British Columbia and New Brunswick sites. Soil samples from British Columbia sites had the highest combined clay and silt content and were composed of illite, albite, kaolinite, and chlorite. The lowest clay content was found in the samples from the Quebec sites. The highest microcline (a potassium feldspar) content was observed in Quebec, Ontario, and Prince Edward Island sites. In contrast to other provinces, samples from Quebec and Ontario sites also included amphibole. Soil samples from Saskatchewan and Manitoba sites also comprised carbonates, i.e., calcite and dolomite. Iron oxides (e.g., goethite) were present in all soils, except the Quebec sites, but their occurrence was rather insignificant. 相似文献
24.
25.
26.
Leong P.H.W. Leung I.K.H. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2002,10(5):550-559
The implementation of a microcoded elliptic curve processor using field-programmable gate array technology is described. This processor implements optimal normal basis field operations in F(2/sup n/). The design is synthesized by a parameterized module generator, which can accommodate arbitrary n and also produce field multipliers with different speed/area tradeoffs. The control part of the processor is microcoded, enabling curve operations to be incorporated into the processor and hence reducing the chip's I/O requirements. The microcoded approach also facilitates rapid development and algorithmic optimization: for example, projective and affine coordinates were supported using different microcode. The design was successfully tested on a Xilinx Virtex XCV1000-6 device and could perform an elliptic curve multiplication over the field F(2/sup n/) using affine and projective coordinates for n=113,155, and 173. 相似文献
27.
CC Leong JV Marley S Loh N Milech BW Robinson MJ Garlepp 《Canadian Metallurgical Quarterly》1997,71(3):476-482
A 56-year-old female with rheumatoid arthritis was admitted because of bilateral hip pain. In a few months of her hospitalization, a relatively abrupt renal dysfunction was emerged besides complement breakdown, and renal biopsy revealed crescentic glomerulonephritis. Immunofluorescence study showed peripheral granular deposits of IgG, IgM, and C3 in the glomeruli. Cresents were predominantly composed of macrophages and glomerular epithelial cells. Amyloid nephropathy, renal vasuculitis, and association of other collagen vascular diseases were negligible for the causative factor. It was suggested that immune complexes were formed in the glomeruli, in which both humoral and cellular immune responses were to be induced, that brought cescents formation in the lesions. Crescentic glomerulonephritis in patients with rheumatoid arthritis is rare and a possible pathogenetic mechanisms involved in the development of renal dysfunction are discussed with the special reference to immune complex-induced inflammation. 相似文献
28.
Cheung Fanny M.; van de Vijver Fons J. R.; Leong Frederick T. L. 《Canadian Metallurgical Quarterly》2011,66(7):593
We review recent developments in the study of culture and personality measurement. Three approaches are described: an etic approach that focuses on establishing measurement equivalence in imported measures of personality, an emic (indigenous) approach that studies personality in specific cultures, and a combined emic–etic approach to personality. We propose the latter approach as a way of combining the methodological rigor of the etic approach and the cultural sensitivity of the emic approach. The combined approach is illustrated by two examples: the first with origins in Chinese culture and the second in South Africa. The article ends with a discussion of the theoretical and practical implications of the combined emic–etic approach for the study of culture and personality and for psychology as a science. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
29.
Y. W. Leong M. B. Abu Bakar Z. A. Mohd. Ishak A. Ariffin B. Pukanszky 《应用聚合物科学杂志》2004,91(5):3315-3326
Three types of mineral fillers—talc, calcium carbonate (CaCO3), and kaolin (10–40 wt % filler loadings)—were compounded with polypropylene (PP) with a twin‐screw extruder. The composites were injection‐molded, and the effects of the filler loading on the mechanical, flow, and thermal properties for the three different types of filled composites were investigated. The aim was to compare their properties and to deduce prospective filler combinations that would yield hybrid PP composites in following studies. The results showed that in most cases, the strength and stiffness of the talc‐filled PP composites was significantly higher than those of the CaCO3‐ and kaolin‐filled PP composites. However, CaCO3, being a nonreactive filler, increased the toughness of PP. The kaolin‐filled PP composites also showed some improvement in terms of strength and stiffness, although the increases in these properties were not as significant as those of the talc‐filled PP composites. The effects of interfacial interactions between the fillers and PP on the mechanical properties were also evaluated with semiempirical equations. The nucleating ability of all three fillers was studied with differential scanning calorimetry, and the strongest nucleating agent of the three was talc, followed by CaCO3 and kaolin. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3315–3326, 2004 相似文献
30.
Y. W. Leong S. Yamaguchi M. Mizoguchi H. Hamada U. S. Ishiaku T. Tsujii 《Polymer Engineering and Science》2004,44(12):2327-2334
An extensive study on the peel strength between a polypropylene (PP) film and PP substrate fabricated using film insert injection molding technique was carried out through a 180° peel test. Injection molding conditions such as barrel temperature, injection speed and holding pressure were varied to gauge their effects on the mechanical and morphological properties. Morphological observations were made at the film‐substrate interfacial regions by means of transmission electron microscopy (TEM). The injection molded products, with the films still attached, were subjected to bending and impact tests to determine if there is any relationship between film‐substrate adhesion and bulk properties. Observation of the load‐displacement curves during the peel test revealed three unique and interesting curves, corresponding to different peeling and film fracture mechanisms. Increases in injection speed, barrel temperature and holding pressure lead to increased bonding between the film and substrate surfaces. The enhancement of bonding between these two polymer surfaces could be attributed to polymer‐polymer interdiffusion. Substantiating evidence from TEM, which shows the fading of the interface as the bond strengthens, further boosts the accuracy of this assumption. The hope that the films could contribute to enhancing bulk properties has been diminished since the bending properties appeared to be similar with or without the film attached. Polym. Eng. Sci. 44:2327–2334, 2004. © 2004 Society of Plastics Engineers. 相似文献