全文获取类型
收费全文 | 20628篇 |
免费 | 1546篇 |
国内免费 | 671篇 |
专业分类
电工技术 | 981篇 |
技术理论 | 3篇 |
综合类 | 1248篇 |
化学工业 | 3691篇 |
金属工艺 | 1007篇 |
机械仪表 | 1256篇 |
建筑科学 | 1592篇 |
矿业工程 | 440篇 |
能源动力 | 557篇 |
轻工业 | 1458篇 |
水利工程 | 333篇 |
石油天然气 | 1048篇 |
武器工业 | 158篇 |
无线电 | 2156篇 |
一般工业技术 | 3039篇 |
冶金工业 | 1142篇 |
原子能技术 | 255篇 |
自动化技术 | 2481篇 |
出版年
2024年 | 59篇 |
2023年 | 274篇 |
2022年 | 394篇 |
2021年 | 577篇 |
2020年 | 488篇 |
2019年 | 433篇 |
2018年 | 461篇 |
2017年 | 583篇 |
2016年 | 523篇 |
2015年 | 701篇 |
2014年 | 832篇 |
2013年 | 1088篇 |
2012年 | 1167篇 |
2011年 | 1246篇 |
2010年 | 1068篇 |
2009年 | 1035篇 |
2008年 | 1101篇 |
2007年 | 1056篇 |
2006年 | 1130篇 |
2005年 | 1100篇 |
2004年 | 695篇 |
2003年 | 656篇 |
2002年 | 606篇 |
2001年 | 525篇 |
2000年 | 676篇 |
1999年 | 731篇 |
1998年 | 628篇 |
1997年 | 555篇 |
1996年 | 493篇 |
1995年 | 452篇 |
1994年 | 333篇 |
1993年 | 248篇 |
1992年 | 207篇 |
1991年 | 170篇 |
1990年 | 134篇 |
1989年 | 116篇 |
1988年 | 89篇 |
1987年 | 43篇 |
1986年 | 45篇 |
1985年 | 43篇 |
1984年 | 19篇 |
1983年 | 4篇 |
1982年 | 12篇 |
1981年 | 13篇 |
1980年 | 11篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1970年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
231.
Langmuir吸附方程的应用 总被引:2,自引:0,他引:2
本文总结了Langmuir方程在吸附分离过程中的应用。利用Langmuir方程得到直观表达混合气组分气体间吸附强弱关系及分离的难易程度的x-y图,推导了Lewis关系式。 相似文献
232.
233.
234.
Li-Piin Sung Joan Jasmin Xiaohong Gu Tinh Nguyen Jonathan W. Martin 《Journal of Coatings Technology and Research》2004,1(4):267-276
Laser scanning confocal microscopy (LSCM) has been used to characterize the changes in film thickness and local surface morphology
of polymer coatings during the UV degradation process. With the noninvasive feature of LSCM, one can obtain thickness information
directly and nondestructively at various exposure times without destroying the specimens or deriving the thickness values
from IR measurement by assuming uniform film ablation. Two acrylic polymer coatings were chosen for the study, and the physical
and chemical changes of the two systems at various exposure times were measured and analyzed. Those measurable physical changes
caused by UV exposure include film ablation, formation of pits and other surface defects, and increases in surface roughness.
It was found in both coatings that changes in measured film thickness by LSCM were not correlated linearly to the predicted
thickness loss using the changes in the CH band obtained by the Fourier Transform Infrared (FTIR) spectroscopy measurements
in the later degradation stages. This result suggested it was not a uniform film ablation process during the UV degradation.
At later stages, where surface deformation became severe, surface roughness and profile information using LSCM were also proven
to be useful for analyzing the surface degradation process
Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 13–14, 2004 in Philadelphia,
PA. 相似文献
235.
Hui Gu Rowland M. Cannon Hans J. Seifert Michael J. Hoffmann Isao Tanaka 《Journal of the American Ceramic Society》2002,85(1):25-32
The nitrogen solubility in the SiO2 -rich liquid in the metastable binary SiO2 -Si3 N4 system has been determined by analytical TEM to be 1%–4% of N/(O + N) at 1973–2223 K. Analysis of the near edge structure of the electron energy loss peak indicates that nitrogen is incorporated into the silicate network rather than being present as molecular N2 . A regular solution model with a positive enthalpy of mixing for the liquid was used to match the data for the metastable solubility of N in the presence of crystalline Si3 N4 and to adjust the computed phase diagram. The solubility of Si3 N4 in fused SiO2 is far less than reported in liquid silicates also containing Al, Mg, and/or Y. Apparently, these cations act as modifiers that break anion bridges in the silicate network and, thereby, allow further incorporation of Si3 N4 without prohibitive amounts of network cross-linking. Finally, indications emerged regarding the diffuse nature of the Si3 N4 -SiO2 interface that leads to amorphous regions of higher N content. 相似文献
236.
本文叙述了VAR I工艺特点及其用于建筑物加固修复的重要性、优越性和应用前景。自制了一套简易实验装置,归纳并阐述了建筑物加固修复用VAR I技术的主要内容。针对国内的情况,提出了该领域亟待开展的研究工作。 相似文献
237.
238.
239.
240.