全文获取类型
收费全文 | 3092篇 |
免费 | 90篇 |
国内免费 | 70篇 |
专业分类
电工技术 | 27篇 |
综合类 | 89篇 |
化学工业 | 498篇 |
金属工艺 | 336篇 |
机械仪表 | 350篇 |
建筑科学 | 233篇 |
矿业工程 | 39篇 |
能源动力 | 90篇 |
轻工业 | 48篇 |
水利工程 | 27篇 |
石油天然气 | 26篇 |
武器工业 | 8篇 |
无线电 | 202篇 |
一般工业技术 | 664篇 |
冶金工业 | 114篇 |
原子能技术 | 45篇 |
自动化技术 | 456篇 |
出版年
2024年 | 2篇 |
2023年 | 37篇 |
2022年 | 29篇 |
2021年 | 50篇 |
2020年 | 58篇 |
2019年 | 49篇 |
2018年 | 43篇 |
2017年 | 53篇 |
2016年 | 65篇 |
2015年 | 89篇 |
2014年 | 121篇 |
2013年 | 159篇 |
2012年 | 156篇 |
2011年 | 243篇 |
2010年 | 170篇 |
2009年 | 196篇 |
2008年 | 156篇 |
2007年 | 164篇 |
2006年 | 170篇 |
2005年 | 138篇 |
2004年 | 123篇 |
2003年 | 180篇 |
2002年 | 121篇 |
2001年 | 87篇 |
2000年 | 86篇 |
1999年 | 80篇 |
1998年 | 77篇 |
1997年 | 59篇 |
1996年 | 43篇 |
1995年 | 50篇 |
1994年 | 28篇 |
1993年 | 20篇 |
1992年 | 23篇 |
1991年 | 22篇 |
1990年 | 9篇 |
1989年 | 16篇 |
1988年 | 9篇 |
1987年 | 12篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 14篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1972年 | 2篇 |
1966年 | 3篇 |
1961年 | 1篇 |
1958年 | 1篇 |
1956年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有3252条查询结果,搜索用时 203 毫秒
81.
Ann Monté Pieter Bauwens Stefaan Maeyaert Jan Doutreloigne 《Journal of the Society for Information Display》2008,16(11):1171-1180
Abstract— A new bistable‐display driver is presented. The innovation in the developed driver is the addition of a new logical block that calculates the most energy‐efficient driving waveforms. In this paper, the algorithms being applied to the row and column waveforms in order to reduce the power consumption are discussed. Some theoretical as well as experimental results are shown, proving a reduction in the power consumption by about 50%. The proposed algorithms are especially important for battery‐powered applications. 相似文献
82.
Kjell Brunnström Katarina Josefsson Börje Andrén 《Journal of the Society for Information Display》2008,16(10):1041-1049
Abstract— The TCO requirements provide well‐known and recognized quality labels for displays. For these requirements to remain useful, they must continuously be reviewed and updated when necessary. The study described here was performed in response to the market trend of designing flat‐panel displays and notebooks with glare panels. The purpose of this study was to investigate subjective responses to display screens of different gloss levels for office workers working on different tasks under normal office‐lighting conditions. The study consisted of three parts, one where the users should set an acceptable reflex level, one where the user should rate their disturbance on a category scale, and one where the visual acuity of the users were investigated whether they were affected by glare or not. The results show that increasing gloss and increasing luminance levels had negative effects on the acceptance and the disturbance of reflexes. There were statistically significant differences in the acceptance and the disturbance levels between screens with low gloss and screens with high gloss, which suggests that screens with the highest gloss levels should be avoided. The study did not show an effect on the performance based on acuity testing. 相似文献
83.
基于实体模型的三维真实感流动模拟软件的研究与开发 总被引:6,自引:0,他引:6
注射成型的流动模拟在预测复杂薄壁型腔的流动行为方面已经比较准确。现行的数值方法主要采用基于中性层的有限元/有限差分/控制体积法,但中性层模型的引入使得模拟软件在应用中具有极大的局限性。本文采用实体模型取代中性层模型,开发了三维真实感流动模拟软件。最后,应用实例证明此模型能够处理由流行CAD系统生成的复杂型腔模型。 相似文献
84.
Haijme Yamamoto Shinji Okamoto Satoe Mitsumine 《Journal of the Society for Information Display》2000,8(3):241-245
Abstract— A red‐emitting phosphor, SrTiO3:Pr3+, for low‐voltage‐type FEDs and VFDs was developed by Futaba Corporation in 1996. The addition of Al or Ga is essential in the preparation of this phosphor because it improves the luminescence efficiency dramatically. For this impurity effect, Futaba Corporation proposed a charge‐compensation mechanism, which was supported by a recent observation of emission lines due to Al3+‐Pr3+ pairs. In addition, it was found that Al also works as a scavenger of planar defects, presumably SrO thin layers interleaved in the SrTiO3 lattice, by forming strontium aluminates. The latter mechanism suggests the possibility that a similar impurity effect can be found in materials with crystal structures, including alkaline‐earth oxide layers (Ruddlesden‐Popper phases). 相似文献
85.
An alternating polyfluorene (APFO) with low band-gap segments named APFO-Green1 has been designed and synthesized for use in optoelectronic devices. The low band-gap segment consists of an electron acceptor (A), fenced by electron donors (D). This D-A-D configuration leads to a partial charge transfer in the polymer backbone, and thereby a low band-gap (1.3 eV). Results obtained from characterization of APFO-Green1 include light absorption and emission at extended wavelengths as well as high hole mobility. Furthermore, blends of the polymer with different fullerene derivatives exhibit unusually high photovoltaic performance at long wavelengths, making this type of conjugated polymers promising for plastic solar cell applications. 相似文献
86.
内压支撑下薄壁管弯曲变形力学分析 总被引:3,自引:0,他引:3
管件内压弯曲又称为管件充液弯曲,具有减小截面畸变,延缓薄壁管内侧失稳起皱,提高弯曲成形极限等优点。支撑内压在其中起到了关键性的作用,对于环向和轴向的应力应变分量具有重要影响。采用塑性理论,对内压和弯矩共同作用下的薄壁管弯曲变形进行理论分析。考虑内压对微元平衡方程的影响,建立一个新的理论分析模型,通过求解非线性方程组,得到薄壁管应力应变的分布规律,定量分析内压对薄壁管应力应变的影响趋势。同时通过将有限元分析得到的应力应变分量的信息,与理论解进行对比发现,理论预测和模拟结果相符合,验证所建立的理论分析模型的可靠性。结果表明,轴向和环向应力随内压升高均大大提高,环向应变随内压升高线性递增,而厚向应变线性减小。 相似文献
87.
《Ergonomics》2012,55(8):1158-1172
AbstractIn the main control rooms of nuclear power plants, operators frequently have to switch between procedure displays and system information displays. In this study, we proposed an operation-unit-based integrated design, which combines the two displays to facilitate the synthesis of information. We grouped actions that complete a single goal into operation units and showed these operation units on the displays of system states. In addition, we used different levels of visual salience to highlight the current unit and provided a list of execution history records. A laboratory experiment, with 42 students performing a simulated procedure to deal with unexpected high pressuriser level, was conducted to compare this design against an action-based integrated design and the existing separated-displays design. The results indicate that our operation-unit-based integrated design yields the best performance in terms of time and completion rate and helped more participants to detect unexpected system failures.Practitioner Summary: In current nuclear control rooms, operators frequently have to switch between procedure and system information displays. We developed an integrated design that incorporates procedure information into system displays. A laboratory study showed that the proposed design significantly improved participants’ performance and increased the probability of detecting unexpected system failures. 相似文献
88.
本文分析了塑料瓶的表面结构特性及其对贴标胶的要求,简介乳液胶的合成过程,讨论了聚会温度、搅拌速度、增粘剂和改性剂对贴标胶的影响。 相似文献
89.
塑料模具材料选用原则及应用 总被引:1,自引:0,他引:1
对塑料模具材料的选用原则和新型模具材料进行了简要的介绍,在此基础上,以成型手机外壳塑料模具为例,对其关键零部件的选材应用进行了主要说明。 相似文献
90.
James Ely Richard Kouzes John Schweppe Edward Siciliano Denis Strachan Dennis Weier 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2006,560(2):373-387
Energy windowing is an algorithmic alarm method that can be applied to plastic scintillator-based radiation portal monitor (RPM) systems to improve operational sensitivity to certain threat sources while reducing the alarm rates from naturally occurring radioactive material. Various implementations of energy windowing have been tested and documented by industry and at Pacific Northwest National Laboratory, and are available in commercial RPMs built by several manufacturers. Moreover, energy windowing is being used in many deployed RPMs to reduce nuisance alarms and improve operational sensitivity during the screening of cargo. This paper describes energy windowing algorithms and demonstrates how these algorithms succeed when applied to “controlled” experimental measurements and “real world” vehicle traffic data. 相似文献