全文获取类型
收费全文 | 240篇 |
免费 | 6篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 27篇 |
金属工艺 | 3篇 |
机械仪表 | 4篇 |
建筑科学 | 1篇 |
能源动力 | 2篇 |
轻工业 | 40篇 |
水利工程 | 1篇 |
无线电 | 38篇 |
一般工业技术 | 32篇 |
冶金工业 | 44篇 |
原子能技术 | 3篇 |
自动化技术 | 48篇 |
出版年
2022年 | 2篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 12篇 |
2012年 | 5篇 |
2011年 | 11篇 |
2010年 | 12篇 |
2009年 | 12篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 10篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 21篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1970年 | 2篇 |
1964年 | 1篇 |
1960年 | 1篇 |
1955年 | 1篇 |
1928年 | 1篇 |
1922年 | 1篇 |
排序方式: 共有246条查询结果,搜索用时 15 毫秒
41.
42.
Naren Noolu Nikhil Murdeshwar Kevin Ely John Lippold William BaeslackIII 《Journal of Electronic Materials》2004,33(4):340-352
Gold-aluminum ball bonds were thermally exposed at constant elevated temperatures, and the resultant phase transformations
studied in detail. The as-bonded microstructure of a Au-Al ball bond essentially consisted of a reaction zone (termed “alloyed
zone” (AZ) in the as-bonded condition) between the Au bump and the bonded Al metallization. It is the growth of the reaction
zone between the Au bump and the bonded Al metallization and also the nonbonded Al metallization during thermal exposure that
gave rise to the various phase transformations. Au4Al, Au8Al3, and Au2Al are the predominant phases that grew across the ball bond until the bonded Al metallization is available to take part in
the interdiffusion reactions. After the complete consumption of the bonded Al metallization, the Au-Al phases reverse transformed
resulting in the formation of the Au4Al phase in the entire reaction zone across the ball bond (RZ-A). The lateral interdiffusion reactions resulted in the nucleation
and the growth of all of the Au-Al phases given by the phase diagram. Kidson’s analysis and Tu et al.’s treatment were extended
to a five-phase binary system to explain the phase transformations in thermally exposed Au-Al ball bonds. It is possible for
all of the Au-Al phases to grow across a ball bond uninhibited as long as the bonded metallization is available. However,
the supply limitation of the bonded metallization gives rise to reverse transformations where Al-rich phases transform to
Au-rich phases and eventually result in the formation of the Au4Al phase in the entire RZ-A. If infinite time is allowed, Au4Al would dissolve; the extent of which is dependent on the solubility of Al in Au. No supply of Au lateral to the bond causes
the reverse transformation of the Au4Al phase, giving rise to the lateral growth of the remaining Au-Al phases. If infinite time is allowed, the lateral phase
transformations would result in the formation of a phase that is dependant on the relative proportion of Au and Al present
in the nonbonded metallization (NBM) and Au4Al below the void line. Hence, the presence of a phase in a particular location of a ball bond is dependent on the time and
temperature of thermal exposure. 相似文献
43.
44.
45.
Silver nanoparticles were deposited spontaneously from their aqueous solution on a porous silicon (PS) layer. The PS acts both as a reducing agent and as the substrate on which the nanoparticles nucleate. At higher silver ion concentrations, layers of nanoparticle aggregates were formed on the PS surface. The morphology of the metallic layers and their SERS activity were influenced by the concentrations of the silver ion solutions used for deposition. Raman measurements of rhodamine 6G (R6G) and crystal violet (CV) adsorbed on these surfaces showed remarkable enhancement of up to about 10 orders of magnitude. 相似文献
46.
47.
This paper presents a method of joining carbon-fibre plies and rigid cellular foam core with stitching for producing light-weight composite structures. After resin infusion and consolidation, the stitched sandwich panel exhibits superior damage tolerance as well as improved transverse properties due to the presence of through-thickness fibre reinforcement. First part of the paper deals with the conceptual development of a multi-needle stitching machine for rigid foams. A needle penetration model for computing the penetration forces has been reported—there is a good agreement between the experimental and theoretical penetration force-displacement curves. A number of sandwich panels with orthogonal and bias stitch orientations have been developed and examined for stitch quality with the aid of X-ray tomography. The paper also presents results from quasi-static indentation, three-point bending and transverse compression tests, on both the stitched and unstitched sandwich panels. 相似文献
48.
Lina Mayuoni-kirshinbaum Zipora Tietel Ron Porat Detlef Ulrich 《European Food Research and Technology》2012,235(2):277-283
During the last few years, there has been a tremendous increase in consumption of pomegranate fruit and juice. Nevertheless, very little is yet known regarding the volatile constituents that determine the unique aroma of pomegranate fruit. We extracted aroma volatiles from fresh ‘Wonderful’ pomegranate juice using solvent-assisted flavour evaporation (SAFE) and headspace solid-phase micro-extraction (HS-SPME) methods, and applied gas chromatography–olfactometry (GC–O) (‘sniffing’) combined with gas chromatography–mass spectrometry (GC–MS) analysis, in order to identify volatile aroma-active compounds. In addition, we performed stir bar sorptive extraction (SBSE) of pomegranate aroma volatiles, coupled with GC–MS analysis, in order to assist in identifying aroma-active compounds. Overall, we tentatively identified 23 volatiles in the SAFE and HS-SPME extracts; they belonged to various chemical classes, including aldehydes, terpenes, alcohols, esters, furans and acids. Using the GC–O nasal impact frequency method, we tentatively detected 12 aroma-active peaks and identified the corresponding odourants by GC–MS. The aroma-active compounds of ‘Wonderful’ pomegranates were ethyl-2-methylbutanoate (fruity, apple), hexanal (green), β-pinene (pine, herbal), β-myrecene (woody, musty), cis-3-hexenal (green), limonene (fruity, musty), cis-2-heptenal (soapy, mushroom), cis-3-hexenol (earthy, grassy), 2-ethylhexanol (floral), β-caryophyllene (fruity, musty), 2(5H)-furanone (sweet, fruity) and β-sesquiphellandrene (terpene, almond). Overall, the flavour of ‘Wonderful’ pomegranate fruit derives from a mixture of various ‘green’, ‘woody’, ‘earthy’, ‘fruity’, ‘floral’, ‘sweet’ and ‘musty’ notes. 相似文献
49.
Weldability of thin sheet metals by small-scale resistance spot welding using high-frequency inverter and capacitor-discharge power supplies 总被引:5,自引:0,他引:5
An investigation has been conducted of the weldability of 0.2-mm-thick sheet aluminum, brass, and copper in small-scale resistance
spot welding using a high-frequency inverter and a capacitor-discharge power supply. The results have been compared to those
of previous investigations using a line-frequency alternating current power supply. The effects of electrode materials and
process parameters on joint strength, nugget diameter, weld-metal expulsion and electrode-sheet sticking were studied. This
work has also provided practical guidelines for selection of power supplies, process parameters (welding current/pulse energy,
welding time/pulse width, electrode forces, etc.) and electrode materials for small-scale resistance spot welding of thin
sheet aluminum, brass and copper. 相似文献
50.
A novel simultaneous unipolar multispectral integrated technology approach for HgCdTe IR detectors and focal plane arrays 总被引:4,自引:0,他引:4
W. E. Tennant M. Thomas L. J. Kozlowski W. V. McLevige D. D. Edwall M. Zandian K. Spariosu G. Hildebrand V. Gil P. Ely M. Muzilla A. Stoltz J. H. Dinan 《Journal of Electronic Materials》2001,30(6):590-594
In the last few years Rockwell has developed a novel simultaneous unipolar multispectral integrated HgCdTe detector and focal
plane array technology that is a natural and relatively straightforward derivative of our baseline double layer planar heterostructure
(DLPH) molecular beam epitaxial (MBE) technology. Recently this technology was awarded a U.S. patent. This simultaneous unipolar
multispectral integrated technology (SUMIT) shares the high performance characteristics of its DLPH antecedent. Two color
focal plane arrays with low-1013 cm−2s−1 background limited detectivity performance (BLIP D*) have been obtained for mid-wave infrared (MWIR, 3–5 m) devices at T>130 K and for long-wave infrared (LWIR, 8–10 m) devices
at T∼80 K. 相似文献