全文获取类型
收费全文 | 2215篇 |
免费 | 316篇 |
国内免费 | 46篇 |
专业分类
电工技术 | 142篇 |
综合类 | 102篇 |
化学工业 | 1054篇 |
金属工艺 | 22篇 |
机械仪表 | 132篇 |
建筑科学 | 28篇 |
矿业工程 | 9篇 |
能源动力 | 12篇 |
轻工业 | 405篇 |
水利工程 | 3篇 |
石油天然气 | 34篇 |
武器工业 | 5篇 |
无线电 | 203篇 |
一般工业技术 | 293篇 |
冶金工业 | 65篇 |
原子能技术 | 14篇 |
自动化技术 | 54篇 |
出版年
2024年 | 12篇 |
2023年 | 66篇 |
2022年 | 101篇 |
2021年 | 122篇 |
2020年 | 77篇 |
2019年 | 83篇 |
2018年 | 79篇 |
2017年 | 106篇 |
2016年 | 111篇 |
2015年 | 101篇 |
2014年 | 121篇 |
2013年 | 144篇 |
2012年 | 188篇 |
2011年 | 148篇 |
2010年 | 124篇 |
2009年 | 139篇 |
2008年 | 89篇 |
2007年 | 126篇 |
2006年 | 102篇 |
2005年 | 99篇 |
2004年 | 75篇 |
2003年 | 66篇 |
2002年 | 54篇 |
2001年 | 40篇 |
2000年 | 36篇 |
1999年 | 31篇 |
1998年 | 21篇 |
1997年 | 13篇 |
1996年 | 23篇 |
1995年 | 16篇 |
1994年 | 7篇 |
1993年 | 13篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有2577条查询结果,搜索用时 11 毫秒
31.
阐述了单、双脚荧光灯的工作原理,并作了对比,对双脚荧光灯灯管在增安型防爆荧光灯中的应用进行了探讨。 相似文献
32.
袁曦明 《武汉理工大学学报(材料科学英文版)》2003,18(1)
1 IntroductionNanoluminescentmaterialisanimportantbranchoftheresearchfieldofluminescentmaterials .Therearemanymethodsofpreparingnanoluminescentmaterials[1] .Inourstudy ,thesol gelmethodwasappliedtosynthesizeY4 Al2 O9∶Eu3+fluorescentpowder.Therearethreediffer e… 相似文献
33.
柴油馏分深度加氢脱硫过程中有色体形成机理的研究 总被引:1,自引:0,他引:1
为了生产含低硫、色度好的柴油产品,采用计算机分子模拟技术研究了柴油馏分深度加氢脱硫(HDS)过程中多环芳烃有色体的形成机理。研究结果显示,柴油馏分中难脱除硫化物4-MDBT、4,6-DMDBT的HDS中间产物生成多环芳烃的反应历程中每步反应的活化能较低,其中的缩合环化反应为吸热反应。模拟产物符合实验事实,表明模拟计算的多环芳烃有色体形成路径是可能的、合理的。 相似文献
34.
Smith E Lally F Stone MA Shaw JS Nash GB Buckley CD Ed Rainger G 《Microscopy research and technique》2006,69(11):875-884
The use of fluorescent probes that allow visualization of leukocyte-endothelial cell (EC) interactions has greatly informed our understanding of leukocyte recruitment. However, effects of these agents on the biological functions of leukocytes are poorly described, leading to concerns about the interpretation of such data. Here we used two flow-based neutrophil adhesion assays to compare the effects of phase contrast illumination (PCI) with high intensity illumination (HII) used for fluorescent microscopy, in the presence or absence of five commonly used fluorochromes. Isolated neutrophils were either (1) perfused across P-selectin to establish a population of rolling cells, which were subsequently activated with fMLP; or (2) perfused across EC activated with TNF-alpha. In the absence of fluorescent dyes, HII did not affect levels of leukocyte adhesion; however, subsequent neutrophil behavior was dramatically altered when compared with cells under PCI, for example, dramatically reducing their migration velocities. In the presence of fluorescent dyes, the effects of HII were exacerbated, although the precise nature of the biological effects of these probes was agent specific. Thus, for the first time, our experiments describe the effects of fluorescent microscopy on the separate stages of the neutrophil recruitment process and reveal a previously unsuspected effect of HII on neutrophil migration. 相似文献
35.
Optimizing imaging parameters for the separation of multiple labels in a fluorescence image 总被引:3,自引:0,他引:3
A theoretical analysis is presented on how to separate the contributions from individual, simultaneously present fluorophores in a spectrally resolved image. Equations are derived that allow the calculation of the signal‐to‐noise ratio of the estimates for such contributions, given the spectral information on the individual fluorophores, the excitation wavelengths and intensities, and the number and widths of the spectral detection channels. We then ask how such imaging parameters have to be chosen for optimal fluorophore separation. We optimize the signal‐to‐noise ratio or optimize a newly defined ‘figure of merit’, which is a measure of efficiency in the use of emitted photons. The influence of photobleaching on the resolution and on the choice of imaging parameters is discussed, as well as the additional resolution gained by including fluorescence lifetime information. A surprisingly small number of spectral channels are required for an almost optimal resolution, if the borders of these channels are optimally selected. The detailed consideration of photobleaching is found to be essential, whenever there is significant bleaching. Consideration of fluorescence lifetime information (in addition to spectral information) improves results, particularly when lifetimes differ by more than a factor of two. 相似文献
36.
37.
38.
利用掺铒光纤光栅实现应变测试中的温度补偿 总被引:2,自引:0,他引:2
为实现光纤光栅应变传感器使用中的温度补偿,设计并制作了掺铒光纤光栅测试系统,利用光纤光栅解调仪和高速数据采集卡分别测试了掺铒光纤光栅的布拉格波长及荧光寿命.通过测量在不同温度及应变作用下的光纤光栅布拉格波长及掺铒光纤荧光寿命,并对实验数据进行线性及非线性拟合,得到了掺饵光纤光栅的温度及应变响应测试结果.测试结果显示利用掺铒光纤光栅可以实现应变测试中的温度补偿,在不同测量范围内选择不同的拟合算法可以提高测量精确度. 相似文献
39.
Eunice C. Nnaji Donald Adgidzi Michael O. Dioha Daniel R.E. Ewim Zhongjie Huan 《The Electricity Journal》2019,32(10):106672
Access to electricity is still a challenge in many parts of sub-Saharan Africa. In Nigeria, over 70% of the rural dwellers do not have access to electricity. The purpose of this paper is to examine the potential of a smart microgrid for off-grid rural electrification in Nigeria. A combination of design thinking and model-based design methodology is employed to select a suitable microgrid configuration and to develop a smart microgrid model. A system consisting of a solar photovoltaic array, battery energy storage and a diesel generator is selected, and the model is developed in Simulink. Demand data from 10 rural communities in Nigeria are used to validate the performance of the model and the potential for demand management is considered. The use of energy efficient light bulbs is found to reduce the peak electricity demand of the case study communities by 42 to 76%. Combining the proposed system with the use of LED bulbs makes the system to have 56 to 81% less net present cost than a system with a diesel generator alone and incandescent light bulbs. The proposed smart microgrid is found to be more suitable for off-grid rural electrification in Nigeria than diesel generators which are currently used for off-grid electrification in Nigeria. 相似文献
40.
针对废旧稀土荧光粉特性,采用高温碱熔与酸浸相结合的方法处理废旧稀土荧光粉,考察碱熔温度、氢氧化钠用量、碱熔时间对稀土浸出率和铝回收率的影响,并对碱熔过程中的物相及形貌变化进行分析.结果表明,在碱熔温度为1050℃、氢氧化钠与废粉质量比为2.5∶1、碱熔时间为2 h 条件下,其稀土浸出率可达98%以上,铝回收率可达98%.通过对碱熔产物物相和形貌分析表明,废粉晶体结构被有效破坏,其中稀土以稀土氧化物形式存在,碱熔产物变成无定型云絮状. 相似文献