首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   204篇
  免费   4篇
  国内免费   1篇
电工技术   1篇
化学工业   59篇
金属工艺   3篇
建筑科学   4篇
能源动力   11篇
轻工业   16篇
水利工程   2篇
石油天然气   1篇
无线电   34篇
一般工业技术   52篇
冶金工业   12篇
原子能技术   2篇
自动化技术   12篇
  2024年   2篇
  2023年   3篇
  2022年   7篇
  2021年   7篇
  2020年   12篇
  2019年   11篇
  2018年   15篇
  2017年   9篇
  2016年   10篇
  2015年   4篇
  2014年   9篇
  2013年   19篇
  2012年   8篇
  2011年   16篇
  2010年   11篇
  2009年   13篇
  2008年   19篇
  2007年   5篇
  2006年   5篇
  2005年   3篇
  2004年   2篇
  2003年   1篇
  2000年   1篇
  1998年   3篇
  1997年   2篇
  1996年   3篇
  1994年   1篇
  1989年   2篇
  1988年   1篇
  1982年   2篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
排序方式: 共有209条查询结果,搜索用时 234 毫秒
1.
Semiconductors - In the present paper, analytical modeling of surface potential and drain current for hetero-dielectric double gate tunnel FET (HDG-TFET) has been done. The two dimensional (2D)...  相似文献   
2.
The UV-Visible absorption spectra of virgin and gamma irradiated (20–800 kGy) CR-39 polymer have been deduced by using Shimadzu Double beam Double Monochromator UV-Visible Spectrophotometer (UV-2550). The existence of the peaks, their shifting and broadening as a result of gamma irradiation has been discussed. Finally the indirect and direct band gap in virgin and gamma irradiated CR-39 has been determined. The values of indirect band gap have been found to be lower than the corresponding values of direct band gap.  相似文献   
3.
Growing interests in multi-criteria decision support applications have resulted in a flurry of efficient skyline algorithms. In practice, real-world decision support applications require to access data from disparate sources. Existing techniques define the skyline operation to work on a single set, and therefore, treat skylines as an “add-on” on top of a traditional Select-Project-Join query plan. In many real-world applications, the skyline dimensions can be anti-correlated such as the attribute pair {price, mileage} for cars and {price, distance} for hotels. Anti-correlated data are particularly challenging for skyline evaluation and therefore have commonly been ignored by existing techniques. In this work, we propose a robust execution framework called SKIN to evaluate skyline over joins. The salient features of SKIN are: (a) effective in reducing the two primary costs, namely the cost of generating the join results and the cost of dominance comparisons to compute the final skyline of join results, (b) shown to be robust for both skyline-friendly (independent and correlated) as well as skyline-unfriendly (anti-correlated) data distributions. SKIN is effective in exploiting the skyline knowledge in both local within individual data sources and across disparate sources—to significantly reduce the above-mentioned costs incurred during the evaluation of skyline over join. Our experimental study demonstrates the superiority of our proposed approach over state-of-the-art techniques to handle a wide variety of data distributions.  相似文献   
4.
5.
Multimedia Tools and Applications - Leap motion sensor provides a new way of interaction with computers or mobile devices. With this sensor, users can write in air by moving palm or finger, thus,...  相似文献   
6.
This research focuses on exploring low-cost and rapid production solutions for fabricating emitters for patch antennas for wireless communication applications. Additive manufacturing technique is employed to fabricate two patch antennas using silver nanoparticle ink on FR4 substrate. Finite-element simulation software, HFSS is used to analyse and predict the theoretical performance of the antenna designs for 2.4?GHz MIMO and 6?GHz wireless data transmission. The fabricated antennas have resonant frequencies closely matching the design values. The work provides a viable solution for fabricating emitters and finally antennas commercially using inkjet printing platform, thus overall reducing the cost and simplifying the process.  相似文献   
7.
The geometrical optimization of aligned hard-soft permanent-magnet nanocomposites is investigated by model calculations. Considered criteria are the shapes of the soft and c-axis-aligned hard phases, the packing fraction of the soft phase, and magnetostatic interactions. Taking into account that the energy product is enhanced via the volume fraction of the soft phase, subject to maintaining coercivity, we find that the best structures are soft-magnetic cubes as well as long rods with a square cross section. Comparing embedded soft cubes with embedded soft spheres of the same size, our nucleation-field analysis shows that the volume fraction of the soft phase is enhanced by 91%, with a coercivity reduction of only 25%. Magnetostatic interactions often but not always deteriorate the permanent-magnet performance, as exemplified by the example of MnBi:FeCo bilayers and multilayers.  相似文献   
8.
Facilitated transport of Cs-137 across supported liquid membranes (SLM) containing a calix-crown ligand viz. caliz[4]arene-bis(crown-6) (CC), calix[4]arene-bis(o-benzocrown-6) (CBC) or calix[4]arene-bis(napthocrown-6) (CNC) was investigated. The feed consisted of dilute nitric acid solutions while the carrier solutions contained mainly CNC in several organic diluents inside the pores of polypropylene (PP) as well as PTFE flat sheet membranes. PTFE membranes containing CNC in a diluent mixture of 2-nitrophenyloctyl ether (NPOE) and n-dodecane were found to have high stability. Selectivity studies were carried out using simulated high level waste (SHLW) as well as fission products obtained from an irradiated natural uranium target.  相似文献   
9.
The purpose of this paper is to demonstrate the relationships between sustainable building design and occupant well-being. It starts with a definition of sustainable design and well-being, and focuses on the relationships between energy performance and occupant feedback. Methodologically it draws on detailed monitoring and surveys of 12 case study office buildings in the UK and India, and the paper uses the data to explore whether energy use and associated CO2 emissions are correlated to occupant satisfaction and comfort. The results demonstrate that increased energy use in the case study buildings is associated with increased mechanisation (e.g. centralised air conditioning) and reduced occupant control. This reduced control in turn is shown to relate to reduced occupant comfort and satisfaction. Finally, the paper reveals that the reported health conditions of occupants correlates strongly with their levels of satisfaction. The overall conclusion is that energy use in typical office buildings is inversely correlated with the well-being of the occupants: more energy use does not improve well-being.  相似文献   
10.
The composite thin films of polyaniline (Pani) with multiwall carbon nanotube (MWNT) and single wall carbon nanotube (SWNT) for hydrogen gas sensing application are presented in this paper. Polyaniline (Pani) was synthesized by chemical oxidative polymerization of aniline using ammonium persulfate in acidic medium. The SWNT and MWNT were doped in Pani in presence of champhor sulfonic acid (CSA) by solution mixing method. Thin films of CNT/Pani composites were prepared by spin coating method. Finally, the response of these composite films for hydrogen gas was evaluated by monitering the change in electrical resistance at room tempeature. It is observed that the SWNT/Pani and MWNT/Pani composite films show a higher response as compare to pure Pani. The structural and optical properties of these composite films have been characterised by X-ray diffraction (XRD) and UV–visible spectroscopy respectively. Surface morphology of these films has also been characterised by optical microscopy.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号