全文获取类型
收费全文 | 144篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 39篇 |
金属工艺 | 4篇 |
机械仪表 | 2篇 |
能源动力 | 8篇 |
轻工业 | 8篇 |
石油天然气 | 1篇 |
无线电 | 14篇 |
一般工业技术 | 27篇 |
冶金工业 | 21篇 |
原子能技术 | 6篇 |
自动化技术 | 19篇 |
出版年
2023年 | 2篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 6篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 6篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1983年 | 3篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有151条查询结果,搜索用时 31 毫秒
61.
62.
63.
Han Ei Chew Vigneswara P. Ilavarasan Mark R. Levy 《Information Technology for Development》2013,19(4):523-542
This article attempts to enrich our understanding of the role that mobile phones play in the empowerment of women in the developing world. We adapt and explicate an innovative social psychological concept, “mattering,” embed it in the literature that examines the impact of mobile phones on social development outcomes, and consider the utility of mattering for the ICT4D community. Mattering is the perception that others are aware of, interested in, and depend on us. Based on a sample of 335 female microentrepreneurs in Chennai, India, we created a valid and reliable measure of mattering and its three dimensions. Mattering was predicted by (1) entrepreneurial expectations, an element of an individual's mindset; (2) social use of mobile phones; and (3) the perceived benefits of mobile phones for maintaining business networks. Findings suggest that mobile phone use plays a significant role in contributing to female entrepreneurs' perception that they matter. 相似文献
64.
In this study, a high performance poly(ether sulfone) (PES) hollow fiber ultrafiltration (UF) membrane has been prepared for removal of natural organic matter (NOM). The membrane was spun from a dope solution containing PES/poly (vinyl pyrrolidone) (PVP 40K)/N‐methyl‐2‐pyrrolidone (NMP) by using a wet‐spinning process. Characterization of the membrane in terms of pure water flux, molecule weight cut‐off (MWCO), and retention for a model humic acid (HA) were conducted, and the fouling resistance was analyzed. The experimental results showed that the membrane had a pure water permeability of 20 × 10?5 L m?2 h?1 Pa?1 and a nominal MWCO of 6000 Da. The results also showed that the membrane retention for humic acid was over 97% and both productivity and selectivity for HA increased with increasing feed velocity. The PES membrane in this study exhibited a much lower fouling tendency than the commercial polysulfone membrane. SEM images revealed that the membrane had an outer dense skin and a porous inner surface. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 430–435, 2006 相似文献
65.
A pilot study for reclamation of secondary treated sewage effluent in Singapore was conducted using a MF/RO system with the capacity of 20 m3/d. A 0.1 μm MF membrane from Asahi and RE-4040-FL RO membrane from Saehan were used in this study. The pilot plant consists of six spiral-wound RO elements. The RO train was configured in single stage. The pilot plant was designed with automatic control system and it was operated continuously (24 h) during the study. Trial runs on various flux rates of the RO membrane at different operating pressures were conducted over 3 months. The pilot results showed that the optimal operation flux rate of the RO membrane ranged from 10 to 15 gal/f2/d (GFD) for this application. The normalized flux after CIP was 97% of the initial one. At a flux rate of 10 GFD and water recovery of 50%, the average operating pressure of 57 psi was noted corresponding to a high normalized flux of 38 L m−2 h−1 MPa−1 at 25°C. Rejections of the RO membrane in terms of conductivity, TOC, ammonium and nitrate were higher than 96%,97%,90% and 85%, respectively. It was concluded that the RO permeate quality in terms of conductivity, turbidity, TOC, ammonium, nitrate, hardness, total bacteria and total coliform matched the quality of high-grade water (NEWater) for use in the electronics industry. 相似文献
66.
L. D Stockton T. L Ng N Maung A. C Wright 《Journal of Materials Science: Materials in Electronics》1998,9(3):207-210
The growth of MgS on GaAs substrates by MOVPE has been previously reported using bis(methylcyclopentadienyl) magnesium (MeCp)2Mg along with various sulphur precursors. Although epitaxial growth is possible with hydrogen sulphide (H2S) and tertiarybutylthiol (tBuSH), they have both been shown to undergo severe parasitic gas phase reactions at room temperature and atmospheric pressure, resulting in MgS layers with poor surface morphology and crystallinity. Preliminary results on the growth of MgS/GaAs(0 0 1) have been reported previously [1]. Here we extend those and report ex situ mass spectrometric investigations of the reaction chemistry between bis(methylcyclopentadienyl) magnesium and tBuSH and an alternative sulphur precursor, ditertiarybutylsulphide (DtBS). No pre-reaction is observed at room temperature as with other sulphur precursors and MgS layers with the rocksalt structure can be grown at temperatures of 450 °C. A decline in MgS growth rate is observed with increasing temperature indicating the participation of a competitive parasitic reaction along with the growth reaction which becomes dominant at high temperatures. Mass spectrometric sampling supports the growth results and suggests tetiarybutylthiol as an intermediate in the growth process. © 1998 Chapman & Hall 相似文献
67.
Ye Hua Nicola Gargiulo Antonio Peluso Paolo Aprea Mladen Eić Domenico Caputo 《化学,工程师,技术》2016,88(11):1739-1745
Multiple‐cycle breakthrough tests of a binary gas mixture of the halogenated anesthetic sevoflurane (SF) and water vapor were performed on both the synthesized chromium‐based metal organic framework (Cr‐MOF) and a conventionally used reference adsorbent. At 1 vol % SF and 50 % relative humidity mixture composition, the Cr‐MOF (MIL‐101) showed a significantly higher SF adsorption capacity, lower water vapor adsorption capacity, and no roll‐up effect compared to the reference sample. After each adsorption measurement, the saturated column was regenerated. MIL‐101 showed higher stability with minor SF capacity loss after 14 cycles, while the reference sample lost about a half of the SF capacity after 17 cycles. 相似文献
68.
When acquiring information systems, public entities face a dilemma. On the one hand, they want to procure the system that best suits their needs, which often requires lengthy dialogues with vendors. At the same time, they are restricted by government regulations that mandate limited dialogue in the interests of transparency and equal opportunities for all vendors. To examine how public entities deal with this, we followed three procurement projects in Norway. We show that this dilemma manifests itself as a dialectic between the thesis of getting the system requirements right and the antithesis of strictly adhering to regulations. Public entities search for a resolution of this dialectic through two syntheses: selecting an appropriate tendering procedure, and learning how to specify requirements through networks of peer public entities. Our findings reveal that the syntheses are possible because the dialectic is actually complimentary, both the thesis and the antithesis are needed to create the joint outcome that satisfies both. The resolution of the dialectic unfolds differently over time. Our study contributes to the relatively neglected stream of IS research on dialectics that explicitly searches for a synthesis while revealing the complementarity of the dialectic. We show how time plays a nuanced role in the resolution of the dialectic situation. 相似文献
69.
Current Status of Extreme Ultraviolet Lithography in Japan 总被引:1,自引:0,他引:1
ASET, Association of Super- advanced Electronics Technologies, has been taking the initiative in developing EUV lithography technology in Japan for the past three years. The aspherical mirror metrology using a visible light point diffraction interferometer (PDI), the wave-front measurement using an at - wavelength PDI, and an at-wavelength reflectometry for multilayers, various imaging simulations, multilayer coatings for the mask, the development of absorber materials for mask patterning, the mask substrate cleaning technique, and various photoresist processes have been developed. The visible light PDI employs a 0.5 -μm pinhole as an aperture to generate an ideal spherical wave-front and can measure a 0.3 - N A mirror maximum. The at - wavelength PDI can measure the wave-front error of the projection optics. The at- wavelength reflectometer can measure the reflectivity of multilayers and the round - robin test is taking place among ASET, the ALS in Lawrence Berkeley, and BESSY in Germany.The mask cleaning technique employs a supersonic hydro- cleaning technique. We have confirmed that the single layer resists can be used for EUV lithography. 相似文献
70.
In this paper, we propose a trajectory-aware handoff algorithm based on position, velocity, signaling delay, and receive signal strength (RSS) of mobile terminal (MT). In order to provide seamless service in modern heterogeneous networks, handoff of the MT should be initiated with correct timing. In our algorithm, velocity of MT is divided into two parts as radial velocity and tangential velocity. For more precise handoff initiation, tangential velocity of MT is neglected, and only radial velocity of MT is considered in handoff decision making. Moreover, before handoff decision, least square line method is applied to RSS of MT to avoid unnecessary back-and-forth handoffs (ping-pong handoffs) between different services. A simulation is provided to compare the proposed algorithm with other various handoff methods, and the results prove this algorithm to have outperformed others. 相似文献