全文获取类型
收费全文 | 12915篇 |
免费 | 1299篇 |
国内免费 | 216篇 |
专业分类
电工技术 | 336篇 |
综合类 | 581篇 |
化学工业 | 8725篇 |
金属工艺 | 256篇 |
机械仪表 | 517篇 |
建筑科学 | 959篇 |
矿业工程 | 187篇 |
能源动力 | 85篇 |
轻工业 | 415篇 |
水利工程 | 153篇 |
石油天然气 | 499篇 |
武器工业 | 58篇 |
无线电 | 153篇 |
一般工业技术 | 1252篇 |
冶金工业 | 96篇 |
原子能技术 | 54篇 |
自动化技术 | 104篇 |
出版年
2024年 | 48篇 |
2023年 | 141篇 |
2022年 | 267篇 |
2021年 | 366篇 |
2020年 | 322篇 |
2019年 | 236篇 |
2018年 | 315篇 |
2017年 | 368篇 |
2016年 | 401篇 |
2015年 | 411篇 |
2014年 | 821篇 |
2013年 | 830篇 |
2012年 | 974篇 |
2011年 | 911篇 |
2010年 | 679篇 |
2009年 | 683篇 |
2008年 | 500篇 |
2007年 | 737篇 |
2006年 | 714篇 |
2005年 | 672篇 |
2004年 | 534篇 |
2003年 | 561篇 |
2002年 | 483篇 |
2001年 | 394篇 |
2000年 | 355篇 |
1999年 | 320篇 |
1998年 | 293篇 |
1997年 | 204篇 |
1996年 | 205篇 |
1995年 | 153篇 |
1994年 | 121篇 |
1993年 | 83篇 |
1992年 | 74篇 |
1991年 | 65篇 |
1990年 | 49篇 |
1989年 | 46篇 |
1988年 | 17篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1985年 | 24篇 |
1984年 | 18篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The depolymerization of high-temperature-vulcanized (HTV) silicone rubbers containing filler silica and alumina into cyclosiloxane monomers and spontaneous recovery of fillers were studied. First, HTV silicone rubber was treated with different types of solvents in the presence of KOH to find that a triad mixture of diethylamine, methanol and hexane was appropriate not only to dissolve the silicone rubber to a suspension but also to separate fillers completely by filtration. The filtrate was distilled to remove solvent first and then give pure cyclosiloxane monomers in 76–84% yields. Second, the rubbers were treated with other types of triad mixture of solvents and bases, e.g. tetramethylammonium hydroxide, hexane and diethylamine. After filtration, residue was again treated with the amine and hexane to recover clean fillers in 83–93% yields. Cyclosiloxane monomers were also obtained from the combined filtrates in 67–78% yields. 相似文献
42.
43.
本项研究对经热壁外延(HWE)生长在GaAs基底上的ZnTe进行分高分辨显微结构的观察,在ZnTe/GaAs界面上不仅存在着混合型全位错的扩展,而且首次发现类似螺旋位错分解的层错,并将其归结为原子在不全位错之后的堆积。 相似文献
44.
Al(OH)3对硅橡胶性能的影响 总被引:1,自引:0,他引:1
综述了Al(OH)3粒径和用量对硅椽胶漏电电流、脉冲电流、耐漏电起痕、表面粗糙程度、电蚀损、介电性能、拉伸强度及漏电电流实验重复性的影响。 相似文献
45.
46.
47.
Kazutaka Chibana Chaedong Kang Masashi Okada Koji Matsumoto Tetsuo Kawagoe 《International Journal of Refrigeration》2002,25(2):83
Water-silicone oil emulsion with an additive, (C2H5O)3SiC3H6NH2, was examined as a heat storage material. A spiral tube used as a heat exchanger was immersed in a low temperature bath and the emulsion was circulated in the tube to make ice continuously. Ice was separated from the ice–liquid suspension in an outlet tank. The amount of formed ice, the temperatures of the inlet and the outlet of the heat exchanger, and the temperatures in the tube wall were measured and the overall heat transfer coefficient and the heat flux through the tube were calculated. Experiments were carried out, varying the flow rate, the temperature of cooling brine, and the thickness of tube wall. The condition under which slurry ice was formed continuously without adhesion of ice to the cooling wall was clarified. Though decrease in the thermal resistance of the tube increased the rate of ice formation or raised the brine temperature, it narrowed the range of the flow rate and of the brine temperature in which slurry ice was formed continuously. 相似文献
48.
Uma Maheswar Rao S. S. M. S. Abdul Majeed C. Venkataseshaiah R. Sarathi 《Bulletin of Materials Science》2002,25(6):473-475
In the present work, tracking phenomena has been studied with silicone rubber material under the a.c. and d.c. voltages following
IEC-587 standards. The surface condition of the tracked zone was analysed using wide angle X-ray diffraction (WAXD) and thermogravimetric
differential thermal analysis (TG-DTA) studies. The tracking time was different for a.c. and d.c. voltages. 相似文献
49.
50.
Ground rubber tire (GRT) powder was maleated in an internal mixer using maleic anhydride and dicumyl peroxide at 160°C. Maleated GRT was characterized by using X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, wettability, and differential scanning calorimetry. The physical properties of the dynamically vulcanized 60 : 40, rubber : plastic composition based on acrylated high‐density polyethylene as the plastic phase and ethylene propylene diene rubber containing maleated GRT as the rubber phase were found to be greater than the corresponding composition containing nonmaleated GRT. The blend was found to be reprocessable, like themoplastic elastomers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 370–378, 2002; DOI 10.1002/app.10348 相似文献