全文获取类型
收费全文 | 1626篇 |
免费 | 42篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 20篇 |
综合类 | 16篇 |
化学工业 | 252篇 |
金属工艺 | 48篇 |
机械仪表 | 25篇 |
建筑科学 | 646篇 |
矿业工程 | 5篇 |
能源动力 | 65篇 |
轻工业 | 75篇 |
水利工程 | 11篇 |
石油天然气 | 3篇 |
无线电 | 68篇 |
一般工业技术 | 268篇 |
冶金工业 | 86篇 |
原子能技术 | 7篇 |
自动化技术 | 83篇 |
出版年
2023年 | 17篇 |
2022年 | 30篇 |
2021年 | 34篇 |
2020年 | 31篇 |
2019年 | 18篇 |
2018年 | 39篇 |
2017年 | 16篇 |
2016年 | 22篇 |
2015年 | 19篇 |
2014年 | 29篇 |
2013年 | 122篇 |
2012年 | 38篇 |
2011年 | 51篇 |
2010年 | 35篇 |
2009年 | 51篇 |
2008年 | 49篇 |
2007年 | 37篇 |
2006年 | 24篇 |
2005年 | 62篇 |
2004年 | 54篇 |
2003年 | 51篇 |
2002年 | 57篇 |
2001年 | 43篇 |
2000年 | 57篇 |
1999年 | 53篇 |
1998年 | 67篇 |
1997年 | 49篇 |
1996年 | 59篇 |
1995年 | 55篇 |
1994年 | 54篇 |
1993年 | 46篇 |
1992年 | 48篇 |
1991年 | 44篇 |
1990年 | 26篇 |
1989年 | 45篇 |
1988年 | 30篇 |
1987年 | 26篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1972年 | 3篇 |
排序方式: 共有1678条查询结果,搜索用时 296 毫秒
61.
Sangita Kumari Karthikeyan Pillai Asha Sharma Ella Mihevc Amit Srivastava Albert Chan 《Particulate Science and Technology》2015,33(5):562-566
Cryogenic aerosol cleaning is a dry cleaning method used in the back end of line (BEOL) semiconductor manufacturing to remove defects from planar hydrophobic surfaces such as SiCOH and SiCxNyHz. Cryogenic aerosol cleaning is preferred over conventional wet cleaning methods as it is a non-contact cleaning method, which uses inert gases to generate sub-micrometer-sized solid aerosol particles that physically remove nanometer-sized contaminants on wafer surfaces. Particle removal mechanism involves detachment of the particles upon impact with aerosol, diffusion, and finally entrainment away from the wafer. In BEOL metal line patterning, particles on the dielectric isolation surfaces translate through the subsequent lithography and copper fill steps in to single or multiple metal line open defects that are yield killers. In this study, we show that the particle removal performance of the standard aerosol cleaning can be enhanced by pre-heating the wafer and use of a higher molecular weight inert gas, namely Ar, for aerosol generation. Both the addition of a Pre-heat step and the use of Ar as the aerosol source showed 47–52% reduction in single and multiple line opens detected through wafer electrical tests during high volume semiconductor manufacturing process. 相似文献
62.
The thermal performance of a passive solar house in Ireland having high energy conservation standards is compared with that of a similar sized conventional dwelling house. In both cases the performance over a meteorological Test Reference Year is assessed using climatically responsive models developed experimentally which predict their internal temperature without heating. The results indicate that the conventional house required over three times as much auxiliary heating as the passive solar house. Solar gain accounted for over half the gross heat demand in the solar house compared to 13% in the bungalow. An added advantage of the increased utilization of solar gain was the estimated reduction in the heating season from nine to six months. 相似文献
63.
Substantial controversy has been produced from the location of over 4000 wind turbines in San Gorgonio Pass, California. The principal point of controversy is the conflicting land use which results from developing wind power in a populated area. A public opinion survey was conducted which demonstrated that the vocal opposition to the wind turbines so commonly expressed is not borne out in fact. While there is indeed some opposition to the development of wind power at this site, particularly in terms of aesthetic degradation, the majority of respondents favoured the development. This level of approval will be of interest to those developing large wind projects elsewhere. 相似文献
64.
65.
Solar stills have been designed to produce water for use in teaching and research laboratories. Various designs and configurations have been constructed and tested over the past 10 years. The original double-surfaced cascade stills (stills A and B) were constructed in aluminium and were rather expensive. Later models termed Series D and E were of galvanised mild steel with stainless steel distillate drains and safety overflow drains. These galvanised steel units suffered from severe corrosion after a few years of operation. The latest design series F, is built in aluminium with stainless steel distillate drains and automatic feed valves. All of the stills produce very pure distilled water (conductance ~1.5 × 10?6 Ω?1 cm?1; pH 6.8–7.4) at a cost which is below that of conventional electrically heated stills. 相似文献
66.
67.
Popat Y. Orlandi M. Gupta S. Bazzanella N. Pillai S. Patel M. K. Miotello A. Patel N. 《Catalysis Letters》2022,152(2):438-451
Catalysis Letters - Mixed transition-metals oxide electrocatalysts have shown huge potential for electrochemical water oxidation due to their earth abundance, low cost and excellent... 相似文献
68.
Ajith Kumar K. K. Srinivasan A. Pillai U. T. S. Pai B. C. Chakraborty M. 《SILICON》2022,14(15):9499-9515
Silicon - The present work aims at understanding the microstructure and mechanical property correlation of hypo (Mg-0.5, 0.7, 1.15 wt% Si) and hyper (Mg-2, 4, 6, 8 and 10 wt% Si) eutectic binary... 相似文献
69.
Gobinath V. K. Rajasekar R. Santhosh S. Moganapriya C. Sri A. Manju Jaganathan S. K. 《SILICON》2022,14(15):9773-9788
Silicon - Antireflection coatings (ARCs) have become one of the key techniques for mass production of Si solar cells. They are generally performed by vacuum processes such as thermal evaporation,... 相似文献
70.
S. Santhosh Kumar M. Devaiah V. Seshu BaiT. Rajasekharan 《Ceramics International》2012,38(2):1139-1147
Silicon carbide particulate reinforced alumina matrix composites were fabricated using DIrected Metal OXidation (DIMOX) process. Continuous oxidation of an Al-Si-Mg-Zn alloy with appropriate dopants along with a preform of silicon carbide has led to the formation of alumina matrix surrounding silicon carbide particulates. SiCp/Al2O3 ceramic matrix composites fabricated by the DIMOX process, possess enhanced mechanical properties such as flexural strength, fracture toughness and wear resistance, all at an affordable cost of fabrication. SiCp/Al2O3 matrix composites were investigated for mechanical properties such as flexural strength, fracture toughness and hardness; the composite specimens were evaluated using standard procedures recommended by the ASTM. The SiCp/Al2O3 ceramic matrix composites with SiC volume fractions from 0.35 to 0.43 were found to possess average bend strength in range 158-230 MPa and fracture toughness was found to be in range of 5.61-4.01 MPa√m. The specimen fractured under three-point loading as observed under scanning electron microscope was found to fail in brittle manner being the dominant mode. Further the composites were found to possess lower levels of porosity, among those prepared by DIMOX process. 相似文献