全文获取类型
收费全文 | 203篇 |
免费 | 21篇 |
国内免费 | 17篇 |
专业分类
电工技术 | 20篇 |
综合类 | 12篇 |
化学工业 | 21篇 |
金属工艺 | 11篇 |
机械仪表 | 7篇 |
建筑科学 | 28篇 |
矿业工程 | 3篇 |
能源动力 | 16篇 |
轻工业 | 3篇 |
水利工程 | 18篇 |
石油天然气 | 2篇 |
武器工业 | 2篇 |
无线电 | 28篇 |
一般工业技术 | 26篇 |
冶金工业 | 15篇 |
原子能技术 | 8篇 |
自动化技术 | 21篇 |
出版年
2024年 | 3篇 |
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 13篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 14篇 |
2012年 | 8篇 |
2011年 | 19篇 |
2010年 | 24篇 |
2009年 | 10篇 |
2008年 | 4篇 |
2007年 | 16篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有241条查询结果,搜索用时 15 毫秒
1.
A Beyer E MüllerH Sigg S StutzC David K EnsslinD Grützmacher 《Microelectronics Journal》2002,33(7):525-529
Germanium islands were embedded in strained silicon quantum wells in order to provide an improved electron confinement in vicinity of the islands. Growth was performed on relaxed SiGe layers. Patterned substrates were used, favouring lattice relaxation as well permitting the fabrication of small Ge islands at deposition temperatures above 500 °C. Photoluminescence analysis reveals a strongly reduced dislocation related signal. The low temperature spectra are dominated by intense signals from the germanium islands. The origin of these signals were investigated by removing the islands by etching, analysing reference samples without a silicon quantum well, varying the germanium deposition and the growth temperature. 相似文献
2.
多电压设计(multiple supply voltage,MSV)是降低SoC功耗的有效方法之一.为便于电压岛供电引脚的放置,提出了一种考虑电压岛边界约束的多电压布图算法.首先,基于切分树表示的布图解特点,提出一种边界检查算法快速确定所有模块的边界信息.其次,以优化功耗为目标采用改进动态规划方法进行多电压分配并构建电压岛.最后,以模拟退火算法作为搜索引擎对芯片的面积、线长和功耗进行协同优化.为减少SA迭代次数,采用了一个两阶段的降温策略.对GSRC电路的实验结果表明,该算法可获得满足边界约束的多电压布图,且和不考虑边界约束时相比,仅在功耗上平均增加5.2%. 相似文献
3.
4.
Pathogenic Bacteria Detection: A Hierarchical 3D Nanostructured Microfluidic Device for Sensitive Detection of Pathogenic Bacteria (Small 35/2018) 下载免费PDF全文
5.
Abstract The present paper tries to estimate the surface water resources potential in some of the major Aegean islands in an effort to provide a means for the continuous development of the region, and, by extension, for similar areas around the world. The islands have to confront the challenge of surviving in a semiarid environment under the constraints of uneven water resources distribution both in space and time. In addition to these, tourism development, industrialization and highly water consumptive life styles have exacerbated perennial problems in water resources and water resources management. The framework of the present effort has a two-prong emphasis. In the first part, a simulation model is presented, which tries to estimate the potential surface runoff under physical, structural organizational, and institutional constraints. The methodology and the premises of the simulation process are delineated. In the second part, the results of the model's application in distinct cases are demarcated. The final product, namely the model and the resulting runoff coefficients, are presented in the form of a standard, which may provide practitioners in the field as well as decisionmakers the means for an initial reference in pertinent developmental efforts. Finally, the conclusions and recommendations raise the question of ecosystem resilience and point towards the urgent and continuous need for the application of integrated water resources management principles. 相似文献
6.
ChunmingWang XingfangWu JieLiu Ning'anXu 《北京科技大学学报(英文版)》2005,12(1):43-47
The free structure of M/A islands in pipeline steel X70 has been studied by transmission electron microscope (TEM). It is shown that the M/A islands are about 1-2 μm in size and distribute at the grain boundary of irregular massive ferrite or acicular ferrite in the microstructure of the steel undergoing TMCP (thermo-mechanical controlled processing). The analysis of diffraction contrast shows that the M/A islands consist of retained austenite and some martensite lamellae different in size and orientation. The microtwinning and midrib exist in the lamella of lenticular martensite, which exhibit the typical character of high-carbon martensite. The influences of TMCP parameters on M/A islands have been studied carefully. With the increase of the cooling speed, the amount of M/A islands decrease slightly and the morphology of M/A islands changes to thin dispersive short bars from thick irregular long strips. 相似文献
7.
This paper presents an evaluation of the efficiency of twelve state of the art wave energy converters in the Atlantic Ocean, in the vicinity of the most important European islands and archipelagos (Iceland, Archipelago of Azores, Madeira Archipelago and Canary Islands). An analysis of the wave conditions in the target areas was first performed by considering a 10-year interval (2004–2013) of wave data provided by the European Centre for Medium-Range Weather Forecasts. For this reason, twenty reference points, all located in water depths of about 50 m, were defined. In order to provide a general picture of the wave potential and also to highlight the presence of some hot spots, several wave parameters, such as significant wave height, mean wave direction and wave power, were evaluated. Then, for every nearshore area, based on the bivariate distributions of the sea states occurrences and also on the power matrix of each device, the performances of each wave energy converter were estimated in terms of the expected electrical power. The results of the present work provide valuable information for the future wave farm projects, which could become in the near future a reliable and effective way to produce energy in island environments. 相似文献
8.
9.
Roberta L Bondar 《Architectural Design》2015,85(4):98-99
‘By 2050 we will have probed the universe even further, peeling back time as we strive for some sense of creation and meaning.’ The world's first neurologist in space, Roberta L Bondar , who conducted international experiments on space mission STS 42 and has subsequently undertaken neurological research with NASA, urges us to look up and into space, which is set to remain a rich area of exploration, scientific investigation and wonder, with the discovery of new planets, light, patterns and materials on the not-so-distant horizon. 相似文献
10.
R. H. Charlier C. P. De Meyer 《The International journal of environmental studies》2013,70(4):249-265
Processing municipal and industrial wastes on land and particularly near inhabited centra has met with increased opposition. An apparent remedy to the problem is the establishment of such facilities offshore, hence various projects to build them on artificial islands. The paper examines a concrete proposal to locate such an island offshore from the Belgian Coast. Oceanographic and environmental aspects of the site are discussed, construction methods reviewed, erosion and corrosion effects looked at. The possibility of utilizing ocean power to provide the necessary operation energy is likewise considered. 相似文献