全文获取类型
收费全文 | 283篇 |
免费 | 7篇 |
专业分类
电工技术 | 2篇 |
综合类 | 3篇 |
化学工业 | 38篇 |
金属工艺 | 5篇 |
机械仪表 | 15篇 |
建筑科学 | 13篇 |
矿业工程 | 1篇 |
能源动力 | 9篇 |
轻工业 | 12篇 |
水利工程 | 5篇 |
石油天然气 | 5篇 |
无线电 | 28篇 |
一般工业技术 | 71篇 |
冶金工业 | 38篇 |
自动化技术 | 45篇 |
出版年
2023年 | 4篇 |
2022年 | 14篇 |
2021年 | 17篇 |
2020年 | 10篇 |
2019年 | 9篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 16篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 21篇 |
2012年 | 17篇 |
2011年 | 19篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 14篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 3篇 |
排序方式: 共有290条查询结果,搜索用时 15 毫秒
101.
Husnain Haider Waris Ali Sajjad Haydar Solomon Tesfamariam Rehan Sadiq 《Clean Technologies and Environmental Policy》2014,16(5):861-874
Solar disinfection (SODIS) is widely practiced all around the world. The process requires variable exposure periods depending upon a number of process parameters (e.g., water turbidity, atmospheric temperature, and cloud cover conditions). This paper describes the development of a mathematical model to estimate required exposure period to achieve Fecal coliforms (FCs) removal for changing process parameters. Daily and hourly solar radiation were estimated and found to be suitable for SODIS application with intensity of 500 W/m2 over a period of 3–5 h/day. Randomized SODIS experiments over a period of 3 years were conducted to consider seasonal and weather variations. Six samples each for five levels of turbidity (0, 5, 10, 20, and 30 NTU) were exposed to sunlight under variable cloud cover conditions on different days during the 3-year sampling period. Samples were collected and analyzed for remaining FCs at different intervals in each sampling day. Analysis of variance revealed that turbidity and percent of cloud cover are the most significant process parameters. It was found that FCs die-off in SODIS bottles followed the first-order kinetics. Different data sets were used for the development and calibration of the model. The calibrated model was further verified against the literature. Simple characteristics curves have also been established for practical application at household level to estimate exposure periods. The study revealed a significant difference between the required exposure periods for different turbidity and cloud cover conditions. 相似文献
102.
103.
104.
Madsen M Takei K Kapadia R Fang H Ko H Takahashi T Ford AC Lee MH Javey A 《Advanced materials (Deerfield Beach, Fla.)》2011,23(28):3115-3127
Recent advancements in the integration of nanoscale, single-crystalline semiconductor 'X' on substrate 'Y' (XoY) for use in transistor and sensor applications are presented. XoY is a generic materials framework for enabling the fabrication of various novel devices, without the constraints of the original growth substrates. Two specific XoY process schemes, along with their associated materials, device and applications are presented. In one example, the layer transfer of ultrathin III-V semiconductors with thicknesses of just a few nanometers on Si substrates is explored for use as energy-efficient electronics, with the fabricated devices exhibiting excellent electrical properties. In the second example, contact printing of nanowire-arrays on thin, bendable substrates for use as artificial electronic-skin is presented. Here, the devices are capable of conformably covering any surface, and providing a real-time, two-dimensional mapping of external stimuli for the realization of smart functional surfaces. This work is an example of the emerging field of "translational nanotechnology" as it bridges basic science of nanomaterials with practical applications. 相似文献
105.
Takei K Fang H Kumar SB Kapadia R Gao Q Madsen M Kim HS Liu CH Chueh YL Plis E Krishna S Bechtel HA Guo J Javey A 《Nano letters》2011,11(11):5008-5012
Nanoscale size effects drastically alter the fundamental properties of semiconductors. Here, we investigate the dominant role of quantum confinement in the field-effect device properties of free-standing InAs nanomembranes with varied thicknesses of 5-50 nm. First, optical absorption studies are performed by transferring InAs "quantum membranes" (QMs) onto transparent substrates, from which the quantized sub-bands are directly visualized. These sub-bands determine the contact resistance of the system with the experimental values consistent with the expected number of quantum transport modes available for a given thickness. Finally, the effective electron mobility of InAs QMs is shown to exhibit anomalous field and thickness dependences that are in distinct contrast to the conventional MOSFET models, arising from the strong quantum confinement of carriers. The results provide an important advance toward establishing the fundamental device physics of two-dimensional semiconductors. 相似文献
106.
Riaz Ahmad Mufti Rehan Zahid Farrukh Qureshi Jawad Aslam Naqash Afzal Muhammad Usman Bhutta 《Lubrication Science》2015,27(4):251-263
Tappet rotation is one of the key tribological parameters that play an important role in component wear. Lack of available techniques has discouraged researchers from performing such studies on real production engines. In this research work, a novel experimental technique has been developed that allows the measurement of tappet rotation speed on any engine having direct acting tappets. This unique method does not require any changes or modifications to the components or engine itself. Using this innovative technique, for the first time, all the tappets of a single camshaft have been instrumented, and tappet speed was measured at different operating conditions verifying that not all the tappets behave in the same way. Experimental results clearly showed that all tappets do not respond to the change in lubricant viscosity and the direction of tappet rotation may be one of the factors influencing the performance. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
107.
In this paper, we present a prototype of a deformation engine to efficiently model and render the damaged structure of vehicles
in crash scenarios. We introduce a novel system architecture to accelerate the computation, which is traditionally an extremely
expensive task. We alter a rigid body simulator to predict trajectories of cars during a collision and formulate a correction
procedure to estimate the deformations of the collapsed car structures within the contact area. Non-linear deformations are
solved based on the principle of energy conservation. Large plastic deformations resulting from collisions are modelled as
a weighted combination of deformation examples of beams which can be produced using classical mechanics. 相似文献
108.
109.
Endothelial dysfunction in cerebral microcirculation during hypothermic cardiopulmonary bypass in newborn lambs 总被引:1,自引:0,他引:1
LC Wagerle P Russo NS Dahdah N Kapadia DA Davis 《Canadian Metallurgical Quarterly》1998,115(5):1047-1054
OBJECTIVES: Inflammatory stimuli or mechanical stresses associated with hypothermic cardiopulmonary bypass could potentially impair cerebrovascular function, resulting in inadequate cerebral perfusion. We hypothesize that hypothermic cardiopulmonary bypass is associated with endothelial or vascular smooth muscle dysfunction and associated cerebral hypoperfusion. Therefore we studied the cerebrovascular response to endothelium-dependent vasodilator, acetylcholine, endothelium-independent nitric oxide donor, sodium nitroprusside, and vasoactive amine, serotonin, in newborn lambs undergoing hypothermic cardiopulmonary bypass (nasopharygeal temperature = 18 degrees C). METHODS: Studies were performed on 13 newborn lambs equipped with a closed cranial window, allowing for direct visualization of surface pial arterioles. Six animals were studied while undergoing hypothermic cardiopulmonary bypass, whereas seven served as nonbypass, warm (37 degrees C) controls. Pial arteriolar caliber (range = 111 to 316 microm diameter) was monitored using video microscopy. RESULTS: Topical application of acetylcholine caused a dose-dependent increase in arteriolar diameter in the control group that was absent in animals undergoing hypothermic cardiopulmonary bypass. Hypothermic cardiopulmonary bypass did not alter the vasodilation in response to sodium nitroprusside. Furthermore, the contractile response to serotonin was fully expressed during hypothermic cardiopulmonary bypass. CONCLUSIONS: The specific loss of acetylcholine-induced vasodilation suggests endothelial cell dysfunction rather than impaired ability of vascular smooth muscle to respond to nitric oxide. It is speculated that loss of endothelium-dependent regulatory factors in the cerebral microcirculation during hypothermic cardiopulmonary bypass may enhance vasoconstriction, and impaired cerebrovascular function may be a basis for associated neurologic injury during or after hypothermic cardiopulmonary bypass. 相似文献
110.