全文获取类型
收费全文 | 1766篇 |
免费 | 31篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 104篇 |
化学工业 | 299篇 |
金属工艺 | 58篇 |
机械仪表 | 32篇 |
建筑科学 | 19篇 |
矿业工程 | 1篇 |
能源动力 | 58篇 |
轻工业 | 150篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 157篇 |
一般工业技术 | 270篇 |
冶金工业 | 524篇 |
原子能技术 | 32篇 |
自动化技术 | 92篇 |
出版年
2023年 | 7篇 |
2022年 | 22篇 |
2021年 | 32篇 |
2020年 | 10篇 |
2019年 | 19篇 |
2018年 | 27篇 |
2017年 | 19篇 |
2016年 | 29篇 |
2015年 | 19篇 |
2014年 | 30篇 |
2013年 | 84篇 |
2012年 | 42篇 |
2011年 | 71篇 |
2010年 | 46篇 |
2009年 | 53篇 |
2008年 | 62篇 |
2007年 | 44篇 |
2006年 | 45篇 |
2005年 | 52篇 |
2004年 | 39篇 |
2003年 | 47篇 |
2002年 | 35篇 |
2001年 | 47篇 |
2000年 | 36篇 |
1999年 | 52篇 |
1998年 | 181篇 |
1997年 | 125篇 |
1996年 | 87篇 |
1995年 | 47篇 |
1994年 | 66篇 |
1993年 | 49篇 |
1992年 | 24篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 20篇 |
1988年 | 11篇 |
1987年 | 18篇 |
1986年 | 16篇 |
1985年 | 29篇 |
1984年 | 9篇 |
1983年 | 16篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 13篇 |
1978年 | 7篇 |
1977年 | 19篇 |
1976年 | 19篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1968年 | 4篇 |
排序方式: 共有1799条查询结果,搜索用时 15 毫秒
71.
Tohru Sekino Toshio Nakajima Satoru Ueda Koichi Niihara 《Journal of the American Ceramic Society》1997,80(5):1139-1148
High-density nickel–dispersed-alumina (Al2 O3 /nickel) composites with superior mechanical properties were obtained by the hydrogen reduction and the hot pressing of alumina–nickel oxide (Al2 O3 /NiO) mixed powders. The mixtures were prepared by using NiO or nickel nitrate (Ni(NO3 )2 · n H2 O) as a dispersion source of nickel metal. Microstructural investigations of the composite fabricated using nitrate powder revealed that fine nickel particles, } 100 nm in diameter, dispersed homogeneously at the matrix grain boundaries, forming the intergranular nanocomposite. High strength (.1 GPa) and high-temperature hardness were registered for the composite that contained a small amount of nickel dispersion. The ferromagnetic properties of nickel, such as high coercive force, were observed, because of the fine magnetic dispersions, which indicates a functional value of structural composites. 相似文献
72.
Enhanced Light Storage of SrAl2O4 Glass‐Ceramics Controlled by Selective Europium Reduction
下载免费PDF全文
![点击此处可从《Journal of the American Ceramic Society》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Takayuki Nakanishi Kazune Watanabe Jumpei Ueda Koji Fushimi Setsuhisa Tanabe Yasuchika Hasegawa 《Journal of the American Ceramic Society》2015,98(2):423-429
A luminescent Eu, Dy: SrAl2O4 glass‐ceramics with high transparency in the visible region was successfully synthesized using the frozen sorbet technique with the control of O2 partial pressure () for the oxidation of Eu2+ ions. The glass‐ceramics include Eu2+, Eu3+, and Dy3+ ions, and thus exhibits three characteristic types of emission bands, 4f–5d at around 520 nm (Eu2+ ions), 4f–4f at 610 nm (Eu3+ ions), and 480 nm (Dy3+ ions). The Eu, Dy: SrAl2O4 glass‐ceramics provide remarkable long‐persistent luminescence under dark condition. The glass‐ceramics also exhibits color‐changing luminescence in the visible region based on their remarkable light storage properties. The luminescent Eu, Dy: SrAl2O4 glass‐ceramics using the frozen sorbet technique with control of are promising materials for application in novel photonic and light storage materials. 相似文献
73.
Effects of pressure and temperature on dyeing acrylic fibres with basic dyes in supercritical carbon dioxide 总被引:2,自引:0,他引:2
The dyeing of acrylic fibre with CI Basic Blue 47 has been investigated using an ammonium carboxylate perfluoropolyether as an auxiliary in order to perform the reverse micellar system in supercritical carbon dioxide media. The basic dye was satisfactorily solubilised in the interior of the reverse micelle in the system, and dyeability in the supercritical carbon dioxide media was excellent, even in the absence of a retardant and/or an acid. The optimum proton-rich condition for dyeing of acrylic fabric is performed in reverse micelle aggregates and the proton-rich water pool is suitable for dye uptake by the fibre even without the presence of additives. Changes in glass transition temperature of acrylic fibre in the carbon dioxide media also influence the dyeing behaviour of acrylic fabric. 相似文献
74.
75.
Plasma surface treatments have been used very often to enhance the surface properties of metallic materials. In this work, Ti6Al4V titanium alloy was treated by nitrogen plasma immersion ion implantation (NPIII) in order to obtain improvements in its surface properties, such as corrosion resistance evaluated here. The microstructure and corrosion behavior of the implanted and unimplanted samples were evaluated, using, XRD, GDOES and potentiodynamic polarization and impedance electrochemical spectroscopy tests in 0.6 M NaCl solution. It was verified that the NPIII created resistant layers to corrosive attacks. In corrosion tests by polarization, the implanted samples showed corrosion current density reduction of about 10 times compared to the Ti6Al4V alloy without treatment. Besides that, it was also observed a reduction of the passive current density of one order of the magnitude. In all the studied cases, the polarization curves were shifted to more positive values of potentials, indicating a lower tendency of these PIII treated surfaces to corrosion. The implantation process produced a thin TiN surface layer followed by Ti2N and then a layer with nitrogen in solid solution, all detected by GDOES combined with X-ray diffraction. These layers promoted an excellent polarization resistance of the Ti6Al4V surfaces on impedance spectroscopy tests also. This better performance in these tests can be correlated with the formation of continuous nitride layer, which could retard chloride ions ingress into the substrate. 相似文献
76.
Investigation of laser consolidation process for metal powder by two-color pyrometer and high-speed video camera 总被引:2,自引:0,他引:2
This paper deals with the measurement of surface temperature on metal powder during the laser consolidation process with two-color pyrometer. Additionally, the aspect of selective laser sintering (SLS) and selective laser melting (SLM) of metal powder is visualized with high speed video camera. As a result, the surface temperature during the laser irradiation was ranged 1520–1810 °C and the consolidation phenomena was classified according to the melting point of metal powder. The metal powder at the heating process cohered intermittently to the melt pool although the laser beam was continuously irradiated to the powder surface. 相似文献
77.
Noboru Nishioka Miyuki Funakoshi Kohji Inamoto Masakuni Uno Akira Ueda 《应用聚合物科学杂志》2010,118(4):2482-2487
Homogeneous grafting of styrene onto cellulose was carried out in a dimethylacetamide/lithium chloride solvent system. The grafted products were added to cellulose/polystyrene (PS) blends as compatibilizers. The thermal decomposition behavior of the blends was investigated by thermogravimetry. The thermal stability of the blends decreased with an increase in grafted product content. The crystallinity of the blends decreased with grafted product content. The microphase‐separated structures of the blends became finer with grafted product content. The glass transition temperatures for cellulose and PS in the blends were lowered with grafted product content. Differences in thermal decomposition behavior of the blends were correlated with compatibility. Thermogravimetry was effective for compatibility estimation in cellulose/PS blends containing grafted products. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
78.
Haruyuki Murakami Hiroshi Ueda Atsushi Ishiyama Norikiyo Koizumi Kiyoshi Okuno 《Electrical Engineering in Japan》2010,171(3):7-15
In the ITER Engineering Design Activity (EDA), four NB3Sn model coils were developed and successfully tested. However, it was revealed that the critical current of the conductor degraded with the increase of electromagnetic force. One of the explanations of this phenomenon is a strand bending caused by enormous electromagnetic force. The authors therefore developed a simulation code using the distributed circuit model to investigate dependency of the critical current performance on the periodic bending deformation. The simulation results were in good agreement with the experiments. The dependence of the critical current on the periodic transverse load, temperature, periodic load pitch, thickness of Ta barrier which prevents Cu stabilizer from being contaminated by Sn, twist pitch of the strand, and RRR of the bronze matrix was investigated using the developed code. The results showed that the critical current degraded less with decreasing the pitch of the transverse load and increasing the Ta barrier thickness. It suggests that the shorter cabling pitch and the larger bending stiffness prevent the critical current degradation. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(3): 7–15, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20923 相似文献
79.
80.
Kikuo Matsui Hideki Shimada Takashi Sasaoka Hirofumi Furukawa Takeshi Ueda Atsuko Yabuki 《国际露天开采、回填与环境杂志》2013,27(3):185-204
Conventional highwall mining extracts coal with an auger machine or a continuous miner from exposed seams at the base of opencut or strip operations. However, under poor strata and high stress conditions, highwall mining cannot be conducted due to pillar and roof failures. In such cases, punch highwall mining is more effective than the conventional highwall mining. This paper describes conventional highwall mining and punch highwall mining systems and discusses the stability of the highwall due to punch highwall mining at opencut coal mines. 相似文献