全文获取类型
收费全文 | 451篇 |
免费 | 21篇 |
国内免费 | 22篇 |
专业分类
电工技术 | 14篇 |
综合类 | 35篇 |
化学工业 | 64篇 |
金属工艺 | 16篇 |
机械仪表 | 10篇 |
建筑科学 | 4篇 |
矿业工程 | 7篇 |
能源动力 | 17篇 |
轻工业 | 16篇 |
水利工程 | 5篇 |
石油天然气 | 9篇 |
无线电 | 29篇 |
一般工业技术 | 88篇 |
冶金工业 | 106篇 |
原子能技术 | 9篇 |
自动化技术 | 65篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 12篇 |
2020年 | 12篇 |
2019年 | 12篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 17篇 |
2015年 | 12篇 |
2014年 | 15篇 |
2013年 | 24篇 |
2012年 | 22篇 |
2011年 | 25篇 |
2010年 | 26篇 |
2009年 | 23篇 |
2008年 | 27篇 |
2007年 | 18篇 |
2006年 | 33篇 |
2005年 | 21篇 |
2004年 | 20篇 |
2003年 | 28篇 |
2002年 | 23篇 |
2001年 | 19篇 |
2000年 | 13篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 12篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有494条查询结果,搜索用时 15 毫秒
1.
2.
Ashok K. Vijh 《Drying Technology》1995,13(1):215-224
An attempt is made to elucidate the electrochemical aspects of the electroosmotic dewatering (EOD) of clays as reported in some recent work, especially that on interrupted DC power electroosmotic dewatering published by Rabie, Mujumdar and Weber (2). These authors showed that the dewatering by EOD stops after the DC power has been on for several minutes or hours; on interruption of their power and on short-circuiting of the electrodes, conditions can be created again for some further dewatering by DC power EOD. This discovery, of Rabie et al. is interpreted as a fuel cell effect and it is shown that it affords clues to several other electrochemical strategies for the possible enhancement of the efficiency of the EOD by DC power.
Further, the open circuit potentials observed by Rabie et al. (2) on the interruption of DC power are given an electrochemical interpretation which leads to quantitative estimates in agreement with the experimental values. 相似文献
Further, the open circuit potentials observed by Rabie et al. (2) on the interruption of DC power are given an electrochemical interpretation which leads to quantitative estimates in agreement with the experimental values. 相似文献
3.
4.
The specific heat at constant pressure, C
p, of aluminum measured by Ditmars, Plint, and Shukla has been reduced to the volume V
0 appropriate for 0 K employing the Murnaghan equation. The C
v0 thus obtained is compared with the theoretical C
v0 calculated in the harmonic and the lowest-order anharmonic approximation from three different pseudopotentials (Harrison, Ashcroft, and Dagens-Rasolt-Taylor) as well as a phenomenological Morse potential. The higher-order (
4) anharmonic contributions are calculated from the same nearest-neighbor Morse potential as in the lowest-order anharmonic theory. The role of the vacancy and the higher-order anharmonic contributions to C
v0 has been examined and we conclude that the
4 contributions to C
v0 are much smaller than the vacancy contribution. After removal of the vacancy contribution, the reduced C
v0 is found to be in excellent agreement with the Ashcroft and Harrison pseudopotentials as well as the Morse potential including the
2 and
4 contributions to C
v0. 相似文献
5.
Xi-Ren 《Annual Reviews in Control》2009,33(1):11-24
We introduce a sensitivity-based view to the area of learning and optimization of stochastic dynamic systems. We show that this sensitivity-based view provides a unified framework for many different disciplines in this area, including perturbation analysis, Markov decision processes, reinforcement learning, identification and adaptive control, and singular stochastic control; and that this unified framework applies to both the discrete event dynamic systems and continuous-time continuous-state systems. Many results in these disciplines can be simply derived and intuitively explained by using two performance sensitivity formulas. In addition, we show that this sensitivity-based view leads to new results and opens up new directions for future research. For example, the n th bias optimality of Markov processes has been established and the event-based optimization may be developed; this approach has computational and other advantages over the state-based approaches. 相似文献
6.
Mental workload is considered to be strongly linked to human performance, and the ability to measure it accurately is key for balancing human health and work. In this study, brain signals were elicited by mental arithmetic tasks of varying difficulty to stimulate different levels of mental workload. In addition, a finite impulse response (FIR) filter, independent component analysis (ICA), and multiple artifact rejection algorithms (MARAs) were used to filter event-related potentials (ERPs). Then, the data consisting of ERPs, subjective ratings of mental workload, and task performance, were analyzed through the use of variance and Spearman’s correlation during a simulated computer task. We found that participants responded faster and performed better in the easy task condition, followed by the medium and high-difficulty conditions, which verifies the validity of the ERP filtering. Moreover, larger P2 and P3 waveforms were evoked as the task difficulty increased, and a higher task difficulty elicited a more enhanced N300. Correlation analysis revealed a negative relationship between the amplitude of P3 and the subjective ratings, and a positive relationship between the P3 amplitude and accuracy. The results presented in this paper demonstrate that a combination of FIR, ICA, and MARA methods can filter ERPs in the non-invasive real-time measurement of workload. Additionally, frontocentral P2, N3, and parietal P3 components showed differences between genders. The proposed measurement of mental workload can be useful for real-time identification of mental states and can be applied to human–computer interaction in the future. 相似文献
7.
从接触电荷转移复合物的光谱测定化合物的电离势 总被引:2,自引:0,他引:2
分子氧可以作为电子受体与很多有机化合物形成接触电荷转移复合物(CCT),从而在长波处产生新的具有最大吸收峰的CCT光谱。 本文采用比较法测定了醚类、醇类,胺类、烃类等三十多种有机化合物的CCT光谱。推导了从CCT光谱计算有机化合物电离势的经验公式,并由此计算了上述三十多种有机化合物的电离势。 相似文献
8.
Osman Allen; Albert Robert; Ridderinkhof K. Richard; Band Guido; van der Molen Maurits 《Canadian Metallurgical Quarterly》2006,32(4):986
A frequency analysis was used to tag cortical activity from imagined rhythmic movements. Participants synchronized overt and imagined taps with brief visual stimuli presented at a constant rate, alternating between left and right index fingers. Brain potentials were recorded from across the scalp and topographic maps made of their power at the alternation frequency between left and right taps. Two prominent power foci occurred in each hemisphere for both overt and imagined taps, one over sensorimotor cortex and the other over posterior parietal cortex, with homologous foci in opposite hemispheres arising from oscillations 180° out of phase. These findings demonstrate temporal isomorphism at a neural level between overt and imagined movements and illustrate a new approach to studying covert actions. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
9.
Wetter Spencer; Peavy Guerry; Jacobson Mark; Hamilton Joanne; Salmon David; Murphy Claire 《Canadian Metallurgical Quarterly》2005,19(4):428
The influence of Huntington's disease (HD) on the olfactory event-related potential (OERP), an electrophysiological measure of olfactory information processing, has not been reported to date. In the present study, olfactory and auditory event-related potentials (ERPs) were recorded monopolarly from Fz, Cz, and Pz electrode sites in 8 patients with HD and 8 age- and gender-matched control participants. Results demonstrated that individuals with HD were delayed compared with controls on the P3 component of the OERP (p 相似文献
10.
施建青 《浙江工业大学学报》1997,(2)
利用格林(Green)函数理论、定域密度近似和费来—狄喇克(Fermi-Dirac)近似,考虑到核子化学势的温度依赖性和表面效应,解析地计算了与温度相关的核子—核光学势实部。由于给出了核子化学势的解析公式,所得到的核子—核光学势实部是完全解析的。 相似文献