全文获取类型
收费全文 | 49125篇 |
免费 | 7056篇 |
国内免费 | 3931篇 |
专业分类
电工技术 | 4912篇 |
技术理论 | 1篇 |
综合类 | 5476篇 |
化学工业 | 4215篇 |
金属工艺 | 1374篇 |
机械仪表 | 2795篇 |
建筑科学 | 3710篇 |
矿业工程 | 1347篇 |
能源动力 | 1319篇 |
轻工业 | 2213篇 |
水利工程 | 1128篇 |
石油天然气 | 2469篇 |
武器工业 | 976篇 |
无线电 | 6755篇 |
一般工业技术 | 5740篇 |
冶金工业 | 1894篇 |
原子能技术 | 655篇 |
自动化技术 | 13133篇 |
出版年
2024年 | 266篇 |
2023年 | 687篇 |
2022年 | 1313篇 |
2021年 | 1521篇 |
2020年 | 1863篇 |
2019年 | 1741篇 |
2018年 | 1563篇 |
2017年 | 2028篇 |
2016年 | 2268篇 |
2015年 | 2281篇 |
2014年 | 3148篇 |
2013年 | 3573篇 |
2012年 | 3648篇 |
2011年 | 3795篇 |
2010年 | 2796篇 |
2009年 | 2948篇 |
2008年 | 2802篇 |
2007年 | 3284篇 |
2006年 | 2974篇 |
2005年 | 2422篇 |
2004年 | 2023篇 |
2003年 | 1866篇 |
2002年 | 1601篇 |
2001年 | 1356篇 |
2000年 | 1167篇 |
1999年 | 908篇 |
1998年 | 713篇 |
1997年 | 653篇 |
1996年 | 498篇 |
1995年 | 417篇 |
1994年 | 363篇 |
1993年 | 295篇 |
1992年 | 223篇 |
1991年 | 185篇 |
1990年 | 144篇 |
1989年 | 121篇 |
1988年 | 79篇 |
1987年 | 77篇 |
1986年 | 57篇 |
1985年 | 66篇 |
1984年 | 49篇 |
1983年 | 34篇 |
1982年 | 42篇 |
1981年 | 35篇 |
1980年 | 31篇 |
1979年 | 30篇 |
1978年 | 13篇 |
1964年 | 12篇 |
1959年 | 12篇 |
1956年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Jonas Berghel 《Drying Technology》2005,23(5):1027-1041
This article presents experimental results for spouted bed drying of sawdust, carried out in a full-scale as well as in a laboratory-scale dryer using air as well as steam as drying media. The aim is to present design parameters for a spouted-bed sawdust dryer that can be used by the industry in designing full-scale dryers. A hydrodynamically stable spouted jet spouted bed was obtained. The heat transfer characteristics of the bed were represented in terms of a volumetric heat transfer coefficient (VHC). When sawdust is dried in a spouted bed, the mean VHC is increasing up to fiber saturation level (20-25% wb) from 40 to 110 W/m3 K. The VHC decreases with the residence time and with an increased static bed height. Gas temperature profiles are also presented for the bottom part of the drying chamber. 相似文献
42.
Lean philosophy: implementation in a forging company 总被引:2,自引:2,他引:0
Ajit Kumar Sahoo N. K. Singh Ravi Shankar M. K. Tiwari 《The International Journal of Advanced Manufacturing Technology》2008,36(5-6):451-462
This research addresses the implementation of lean philosophy in a forging company with a focus on radial forging production
flow lines. Here, the prime motive is to evolve and test several strategies to eliminate waste on the shop floor. In this
research, a systematic approach is suggested for the implementation of lean principles. This paper describes an application
of value stream mapping (VSM). Consequently, the present and future states of value stream maps are constructed to improve
the production process by identifying waste and its sources. Furthermore, Taguchi’s method of design of experiments is pursued
here to minimize the forging defects produced due to imperfect operating conditions. A noticeable reduction in set-up time
and work-in-process (WIP) inventory level is substantiated. Finally, we conclude with a discussion of managerial implications
and the future scope of research. 相似文献
43.
Takeshi Shiofuku Norihiro Abe Yoshihiro Tabuchi Hirokazu Taki Shoujie He 《Artificial Life and Robotics》2008,13(1):290-293
This paper presents an approach of measuring in real-time the vector of finger that is pointing to an object. DSP is used
in the operation processing unit in order to do the real-time processing. The steps include the extraction of flesh-colored
regions from an image, the labeling of the flesh-colored regions, and the detection of two characteristic positions on the
finger so that the direction that the finger is pointing at will be calculated. The entire process takes about 29 msec, which
makes it possible to have the frame rate of 34 fps. With this frame rate, this measurement approach is considered real-time
and promising to be merged into other application systems.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
44.
The Clopper-Pearson confidence interval has ever been documented as an exact approach in some statistics literature. More recently, such approach of interval estimation has been introduced to probabilistic control theory and has been referred as non-conservative in control community. In this note, we clarify the fact that the so-called exact approach is actually conservative. In particular, we derive analytic results demonstrating the extent of conservatism in the context of probabilistic robustness analysis. This investigation encourages seeking better methods of confidence interval construction for robust control purpose. 相似文献
45.
46.
介绍了一种基于人工神经网络(ANN)的声目标识别系统,概述了用MATLAB专用工具箱对神经网络权值进行训练及仿真的过程,叙述了ANN目标识别系统的数字信号处理器(DSP)实时实现过程,并着重分析定点实现过程中程序变量的定标、非线性运算的实现、溢出的处理等关键步骤.对不同字长的识别结果进行比较表明,基于定点实时实现的系统数据保持很高的精度,可以得到与浮点处理相同的识别率. 相似文献
47.
48.
RT-AGVS是物流管理中十分重要的课题,车辆位置监测网是其重要的组成部分。本文详细介绍了一个基于单片机系统的车辆位置实时监测网,本监测网设计先进,性能价格比高,它的设计方法和技术对其他许多领域有借鉴作用。 相似文献
49.
球罐活性缺陷的模糊评定方法 总被引:6,自引:0,他引:6
根据国内外有关标准和文献,利用模糊数学中的模糊描述和隶属度等概念,首次采用多级模糊综合评定理论,分层次地把活性缺陷的主要监测信息(即声发射源信息)和专家们的经验考虑在内,建立在用球形贮罐声发射源严重度多级模糊综合评定模型和方法,并编制计算机数据分析和处理程序,使评定结果趋于更合理和可靠.并给出在用球形贮罐声发射源严重度多级模糊综合评定算例,结果表明,该评定方法可以达到定量化的程度,与局部无损复验结果有良好的一致性. 相似文献
50.
中针对变井储试井分析问题,给出了确定变井储系数及计算续流量的方法,并用反褶积分析积分析方法解释了未出现径向流的早期测压数据,给出了解决早期试井资料分析问题的有效方法。 相似文献