全文获取类型
收费全文 | 278篇 |
免费 | 20篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 17篇 |
综合类 | 19篇 |
化学工业 | 29篇 |
金属工艺 | 2篇 |
机械仪表 | 25篇 |
建筑科学 | 32篇 |
矿业工程 | 35篇 |
能源动力 | 2篇 |
轻工业 | 4篇 |
水利工程 | 11篇 |
石油天然气 | 13篇 |
武器工业 | 2篇 |
无线电 | 23篇 |
一般工业技术 | 26篇 |
冶金工业 | 19篇 |
原子能技术 | 7篇 |
自动化技术 | 41篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 21篇 |
2012年 | 16篇 |
2011年 | 15篇 |
2010年 | 18篇 |
2009年 | 21篇 |
2008年 | 14篇 |
2007年 | 18篇 |
2006年 | 14篇 |
2005年 | 17篇 |
2004年 | 13篇 |
2003年 | 14篇 |
2002年 | 13篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1983年 | 1篇 |
排序方式: 共有307条查询结果,搜索用时 15 毫秒
91.
J. Pirkkalaniemi M. Waltari M. Kosunen L. Sumanen K. Halonen 《Analog Integrated Circuits and Signal Processing》2003,35(1):33-45
A 14-bit current-steering DAC utilizing parallel current memories operating as a deglitcher is presented. The high linearity of the current memories is based on a memory MOS transistor biased in the triode region and a bootstrapped sampling switch. The prototype circuit is implemented using a 0.35-m BiCMOS (SiGe) technology and it occupies 5.7 mm2 of silicon area. According to measurements, THD is –66.8 dBc with a 9.1-MHz input signal and 30-MHz clock frequency. Two-tone test gives intermodulation levels below 68 dBFS at 40-MS/s sampling rate. The power dissipation is 370 mW from a 3-V supply. 相似文献
92.
This article investigates performances of MCMC methods to estimate stochastic volatility models on simulated and real data. There are two efficient MCMC methods to generate latent volatilities from their full conditional distribution. One is the mixture sampler and the other is the multi-move sampler. There is another efficient method for latent volatilities and all parameters called the integration sampler, which is based on the mixture sampler. This article proposes an alternative method based on the multi-move sampler and finds evidence that it is the best method among them.JEL classification C22 相似文献
93.
Piechocki-Minguy A Plaisance H Schadkowski C Sagnier I Saison JY Galloo JC Guillermo R 《The Science of the total environment》2006,366(1):55-64
Personal NO(2) exposure measurements were achieved during two campaigns in a large northern France city. These campaigns were following an innovating approach based on sequential exposure measurements by diffusive samplers distinguishing four categories of microenvironments ("home", "other indoor places", "transport" and "outdoors"). The objective of these campaigns was to obtain NO(2) personal exposure data in different microenvironments and to examine the determinants of personal exposure to this pollutant. Each campaign comprised two 24-h sampling periods: one during a working day and the second during the weekend. The average total NO(2) personal exposure ranged from 17 microg m(-3) for the summer weekend samplings to 38 microg m(-3) for the winter weekday samplings. The highest levels were found in transports and outdoors, the intermediate ones in other indoor places and the lowest in homes. Despite their weak levels, indoor environments contributed for more than 78% to total NO(2) personal exposure because of more time spent in these living places. A Multiple Correspondence Analysis (MCA) highlighted the determinants of NO(2) personal exposure in the "home" and "transport" microenvironments. This led to a classification of NO(2) personal exposure levels according to different means of transport: from the lowest to the highest exposure levels, train, tramway or underground, bicycle, car or motorcycle. In homes, the rise of NO(2) personal exposures is mainly due to the use of gas stoves and gas heating and the absence of automatic airing system. A classification of NO(2) personal exposure levels was set up according to the characteristics of homes. An analysis of correlations between the home NO(2) personal exposures and outdoor concentrations measured by fixed ambient air monitoring stations showed weak relations suggesting that the data of these stations are poor predictors of NO(2) personal exposures in homes. 相似文献
94.
河床泥沙测验需要使用专门的泥沙取样器,通过对目前国内市场上常见床沙采样器存在的各种不足进行了分析,研究了一种钻杆外加防护套管,钻头在套管内获取泥沙样品的新型河床泥沙取样器。这种新型河床泥沙取样器能适应各类床沙取样,深度可调,拆装方便,性能可靠,能保证泥沙样品的原状和完整。 相似文献
95.
96.
《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,656(1):11-38
The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given. 相似文献
97.
针对环形光刀取样式高能激光光强分布测量系统的要求,研制了以圆弧反射面环形光刀架构的光取样器,实现了对激光束的在线取样测量。光取样器的取样光刀外形设计为环形光刀,可对取样光束进行周向扩展,满足半数以上探测器接收取样空间光信号的要求;取样光刀反射面设计为圆弧形,可对取样光束进行切向扩展,使其在增大衰减倍率的同时降低系统对光的难度。通过光取样器具体设计参数的计算,获得了满足探测单元与反射光束耦合孔径角要求的参数设计范围。实验表明,研制的光取样器可有效用于大面积高能激光束的在线测量。 相似文献
98.
介绍了全自动煤炭汽车采制样机的构成模块;分析了车辆信息采集、三维坐标点选取、采样方式及采样点坐标的测量、采样系统编码模块、采样系统与其他系统的接口等功能;该系统的应用实现了煤炭采制样系统真正意义上的全自动控制,引领了采样机控制技术的发展方向。 相似文献
99.
New technical solutions are proposed for sampling soil, snow, and loose materials with improved operating characteristics
that may be used in measuring the weight concentration of O-pinacolyl methyl phosphonate in ecological, geological, geochemical,
and microbiological research.
Translated from Izmeritel’naya Tekhnika, No. 4, pp. 68–71, April, 2009. 相似文献
100.
Jacek Koronacki Author Vitae Author Vitae Wojciech Niemiro Author Vitae 《Pattern recognition》2005,38(2):241-250
We propose a new algorithm for positron emission tomography (PET) image reconstruction. The algorithm belongs to the family of Markov chain Monte Carlo methods with auxiliary variables. The idea is to iteratively generate hidden variables at one step and use them for image restoration at another step. The well-known model of Vardi et al. (J. Amer. Statist. Assoc. 80 (1985) 8) for PET is combined with the Bayesian model of Lasota and Niemiro (Pattern Recognition 36 (2003) 931) for the underlying images. This latter model takes advantage of the fact that medical images often consist of relatively few grey-levels of unknown intensity. The algorithm of Lasota and Niemiro (Pattern Recognition 36 (2003) 931) is used in the image restoration part of the PET algorithm, essentially as a noise-filtering and smoothing device. It is now equipped with an additional data reconstruction step. We include simulation results which suggest that the method is truly reliable. We also describe a version of the basic algorithm, in which a random simulation step is replaced by computation of expected value, similarly as in the EM algorithm. 相似文献