全文获取类型
收费全文 | 159篇 |
免费 | 4篇 |
国内免费 | 5篇 |
专业分类
化学工业 | 49篇 |
金属工艺 | 3篇 |
机械仪表 | 9篇 |
建筑科学 | 4篇 |
矿业工程 | 1篇 |
能源动力 | 9篇 |
轻工业 | 11篇 |
水利工程 | 1篇 |
无线电 | 6篇 |
一般工业技术 | 31篇 |
冶金工业 | 8篇 |
原子能技术 | 1篇 |
自动化技术 | 35篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 16篇 |
2021年 | 15篇 |
2020年 | 12篇 |
2019年 | 15篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 12篇 |
2015年 | 5篇 |
2014年 | 9篇 |
2013年 | 12篇 |
2012年 | 8篇 |
2011年 | 5篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 1篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 1篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
排序方式: 共有168条查询结果,搜索用时 15 毫秒
111.
ABSTRACTMultiple mode couplings in topological coherent modes of Bose–Einstein condensate are considered, by introducing an external alternating (resonating) field in the system. This analysis is based on the analytical solutions of nonlinear Gross–Pitaevskii equation for a trapped Bose gas at nearly absolute zero temperature. The dynamics of fractional populations of the generated coherent modes are analysed, particularly for a three-level system in the limit of small to large detuning of the intermediate state. These coupled topological modes, though nonlinear, are analogous to a resonant atom and exhibit a variety of significant non-trivial phenomena (effects), like: dynamic phase transitions, interference patterns, critical phenomena, mode-locking and chaotic motion. 相似文献
112.
Recently, mobile-to-mobile (M2M) cooperative network technology has gained considerable attention for its promise of enhanced
system performance with increased mobility support. As this is a new research field, little is known about the statistical
properties of M2M fading channels in cooperative networks. So far, M2M fading channels have mainly been modeled under the
assumption of non-line-of-sight (NLOS) conditions. In this paper, we propose a new model for M2M fading channels in amplify-and-forward
relay links, where it is assumed that a line-of-sight (LOS) component exists in the direct link between the source mobile
station and the destination mobile station. Analytical expressions will be derived for the main statistical quantities of
the channel envelope, such as the mean value, variance, probability density function (PDF), level-crossing rate (LCR), and
average duration of fades (ADF) as well as the channel phase. Our results show that the statistical properties of the proposed
M2M channel are quite different from those of double Rayleigh and double Rice channels. In addition, a high-performance channel
simulator will be presented for the new M2M channel model. The developed channel simulator is used to confirm the correctness
of all obtained theoretical results by simulations. 相似文献
113.
Tauriq Uzzaman Sidra Zawar Muhammad Tamoor Ansar Shahid M. Ramay Asif Mahmood Shahid Atiq 《Ceramics International》2021,47(8):10733-10741
The quest for cost-efficient electro-active materials exhibiting high specific capacitance is currently a key focus in energy-related research. Owing to their high capacitance values, metal oxides (MOs) are preferably being utilized for energy storage applications as electrode materials in supercapacitors. However, the electrochemical performance of MOs is hindered due to less specific surface area and high tendency towards aggregation. Therefore, tuning in electrochemical activity of MOs is essential. In this framework, NiFe2O4 was prepared using a facile and cost-effective citrate-gel followed by auto-ignition method, and was incorporated with activated carbon contents to tune the electrochemical performance. Formation of inverse spinel structure of NFO and its stability throughout the compositions was examined using X-ray diffraction analysis. Well-dispersed, spherical and porous morphological features were visualized using a field emission scanning electron microscope. The electrochemical analysis was conducted using CH instruments 660 E via freshly prepared 4 M KOH solution. Cyclic voltammetry was carried out at constant potential window of 0.25–0.65 V and different scan rates (0.009–0.08 Vs-1). The pseudo-capacitive behavior was perceived from occurrences of oxidation/reduction peaks. In addition, charge/discharge curves revealed cyclic stability over long range cycles. Specific capacitance, discharge time, energy and power density values were also measured for all the compositions and NFO with 1% activated carbon was found to be the most suitable candidate for use as electrode materials in the present work. 相似文献
114.
Physiological transport phenomena often feature ciliated internal walls. Heat, momentum, and multispecies mass transfer may arise and additionally non‐Newtonian biofluid characteristics are common in smaller vessels. Blood (containing hemoglobin) or other physiological fluids containing ionic constituents in the human body respond to magnetic body forces when subjected to external (extracorporeal) magnetic fields. Inspired by such applications, in the present work we have considered the forced convective flow of an electrically conducting viscoelastic physiological fluid through a ciliated channel under the action of a transverse magnetic field. The presence of deposits (fats, cholesterol, etc.) in the channel is mimicked with a Darcy porous medium drag force model. The effect of energy loss is simulated via the inclusion of viscous dissipation in the energy conservation (heat) equation. The velocity, temperature, and pressure distribution are computed in the form of infinite series constructed by Adomian decomposition method and numerically evaluated in a symbolic software (Mathematica). The influence of Hartmann number (magnetic parameter), Jeffrey first and second viscoelastic parameters, permeability parameter (modified Darcy number), and Brinkman number (viscous heating parameter) on velocity, temperature, pressure gradient, and bolus dynamics is visualized graphically. 相似文献
115.
116.
Multimedia Tools and Applications - The meanings of passing information from one side to other side by a conventional way is been changed because of internet and communication technology. The... 相似文献
117.
Faizah Altaf Rida Batool M. Ashfaq Ahmad Rizwan Raza M. Ajmal Khan Ghazanfar Abbas 《Iranian Polymer Journal》2018,27(6):413-422
An environmental-friendly synthesis of polymer clay nanocomposites (PCNs) was carried out by incorporation of nanoclay into polymer matrix for their potential application as sorbent of metals present in aqueous media. Polyacrylonitrile was chemically grafted onto 77% vinyl triethoxysilane-modified sepiolite. The polymerization was carried out with benzoyl peroxide (BPO, C14H10O4) initiator in three different weight ratios of 1.0, 2.0, and 3.0%. The maximum polymer grafting of about 83% was obtained in nanocomposite initiated by 2.0% ratio of BPO. The surface modification of nanocomposites was carried out using hydroxyl amine hydrochloride (NH2OH·HCl). The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffractometry, thermogravimetric analysis, and Brunauer–Emmett–Teller technique. The copper removal tendency of nanocomposites was studied by atomic absorption spectroscopy. The maximum adsorption of copper was 86%, which could be achieved by nanocomposites synthesized with 2% initiator. The results have revealed the practical potential of the prepared PCN as efficient adsorbents. 相似文献
118.
Jamshed Akbar Shahid Iqbal Fozia Batool Abdul Karim Kim Wei Chan 《International journal of molecular sciences》2012,13(11):15387-15400
119.
Z. Imran S.S. Batool M.Q. Israr J.R. Sadaf M. Usman H. Jamil M.Y. Javed M.A. Rafiq M.M. Hasan O. Nur M. Willander 《Ceramics International》2012,38(4):3361-3365
Here we present an electrospinning technique for the fabrication of cadmium titanate/polyvinyl-pyrrolidone composite nanofibers. The composite nanofibers are then annealed at 600 °C to obtain ilmenite rhombohedral phase cadmium titanate nanofibers. The structure, composition, thermal stability and optical properties of as synthesized and annealed cadmium titanate nanofibers are characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy and ultraviolet–visible spectroscopy. The average diameter and length of the nanofibers are found to be ~150–200 nm and ~100 μm, respectively. 相似文献
120.