全文获取类型
收费全文 | 10123篇 |
免费 | 2193篇 |
国内免费 | 1057篇 |
专业分类
电工技术 | 371篇 |
技术理论 | 2篇 |
综合类 | 833篇 |
化学工业 | 526篇 |
金属工艺 | 173篇 |
机械仪表 | 617篇 |
建筑科学 | 485篇 |
矿业工程 | 288篇 |
能源动力 | 118篇 |
轻工业 | 256篇 |
水利工程 | 545篇 |
石油天然气 | 103篇 |
武器工业 | 68篇 |
无线电 | 3228篇 |
一般工业技术 | 923篇 |
冶金工业 | 159篇 |
原子能技术 | 28篇 |
自动化技术 | 4650篇 |
出版年
2024年 | 106篇 |
2023年 | 368篇 |
2022年 | 473篇 |
2021年 | 564篇 |
2020年 | 547篇 |
2019年 | 530篇 |
2018年 | 567篇 |
2017年 | 613篇 |
2016年 | 661篇 |
2015年 | 712篇 |
2014年 | 928篇 |
2013年 | 818篇 |
2012年 | 908篇 |
2011年 | 915篇 |
2010年 | 570篇 |
2009年 | 541篇 |
2008年 | 488篇 |
2007年 | 517篇 |
2006年 | 483篇 |
2005年 | 397篇 |
2004年 | 322篇 |
2003年 | 269篇 |
2002年 | 166篇 |
2001年 | 134篇 |
2000年 | 127篇 |
1999年 | 99篇 |
1998年 | 106篇 |
1997年 | 71篇 |
1996年 | 69篇 |
1995年 | 40篇 |
1994年 | 51篇 |
1993年 | 43篇 |
1992年 | 38篇 |
1991年 | 12篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 15篇 |
1987年 | 4篇 |
1986年 | 43篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 11篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Shane Y. Hong 《Journal of Intelligent Manufacturing》1993,4(3):233-241
One major bottleneck in the automation of the drilling process by robots in the aerospace industry is drill condition monitoring. This paper describes a system approach to solve this problem through the advancement of new machine design, sensor instrumentation, metal-cutting research, and intelligent software development. All drill failures can be detected and distinguished: chisel edge wear, flank wear, crater wear, margin wear, corner wear, breakage, asymmetry, lip height difference, and chipping at lips. However, in the real manufacturing environment, different workpiece materials, drill size, drill geometry, drill material, cutting speed, feed rate, etc. will change the criteria for judging the drill condition. The knowledge base used for diagnosing the drill failures requires a huge data bank and prior exhaustive testing. A self-learning scheme is therefore introduced to the machine in order to acquire the threshold history needed for automatic diagnosis by using the same new tool under the same drilling conditions. 相似文献
12.
Marcela Brugnach Andrew Tagg Florian Keil Wim J. de Lange 《Water Resources Management》2007,21(7):1075-1090
The use of computer models offers a general and flexible framework that can help to deal with some of the complexities and
difficulties associated with the development of water management plans as prescribed by the Water Framework Directive. However,
despite the advantages modelling presents, the integration of information derived from models into policy is far away from
being trivial or the norm. Part of the difficulties of this integration is rooted in the lack of confidence policy makers
have on the incorporation of modelling information into policy formulation. In this paper we examine the reasons for this
apparent lack of confidence and explore how some tools, presently in use, address this problem. We conclude that public confidence
in models is highly dependent on the way uncertainties are addressed and suggest possible directions of action to improve
the current situation. Four real case studies illustrate how computer models have been used in The Netherlands for carrying
out management plans at regional and national scale. We suggest that the solution to integrate modelling information into
policy formulation lies on both the modelling and the policy-making communities. 相似文献
13.
本文所提出的新算法 BANDC 是 BAyes Normal Dynamic Clustering 的缩写。这个算法的目的是从遥感图象识别地理环境。它的优点是:能由机器自动按照图象估算出分类器的参数;作为一种特殊的 Bayes 分类器,它能够依靠计算机估算出{wi}的先验概率,于是能剔除野点,提高分类器的鲁棒性。这个算法的关键是应用拟合法从灰度等级直方图估算出参数。 相似文献
14.
15.
不用专门相移装置的三维面形测量 总被引:1,自引:1,他引:0
提出一种不需要专用相移装置实现相移,主要利用数字图像处理技术实现三维面形测量的方法,研究结果表明,用原干涉图像及1幅以上的移值条纹图主可能实现物体三维面形的测量。 相似文献
16.
Evgenia Adamopoulou Konstantinos Demestichas Panagiotis Demestichas Michael Theologou 《International Journal of Communication Systems》2008,21(3):311-330
Cognitive radio systems dynamically reconfigure the algorithms and parameters they use, in order to adapt to the changing environment conditions. However, reaching proper reconfiguration decisions presupposes a way of knowing, with high enough assurance, the capabilities of the alternate configurations, especially in terms of achievable transmission capacity and coverage. The present paper addresses this problem, firstly, by specifying a complete process for extracting estimations of the capabilities of candidate configurations, in terms of transmission capacity and coverage, and, secondly, by enhancing these estimations with the employment of a machine learning technique. The technique is based on the use of Bayesian Networks, in conjunction with an effective learning and adaptation strategy, and aims at extracting and exploiting knowledge and experience, in order to reach robust (i.e. stable and reliable) estimations of the configurations' capabilities. Comprehensive results of the proposed method are presented, in order to validate its functionality. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
17.
航空放射性遥感系统采用航空γ能谱仪,在空中飞行探测地表放射性,能够快速进行大面积环境放射性调查。结合已经开始进行的首次大面积航空放射性遥感调查工作,简要介绍了航空放射性遥感系统构成、核探测γ能谱测量和数据处理技术。对系统转换因子刻度和剥离系数刻度方法进行了讨论,并对初步应用情况进行了总结。 相似文献
18.
David P. Cormode Jason J. Davis Paul D. Beer 《Journal of Inorganic and Organometallic Polymers and Materials》2008,18(1):32-40
Disulfide and dithiocarbamate functionalized porphyrins have been synthesized and used as protecting ligands for gold nanoparticle
formation either via ligand substitution reactions or by direct synthesis. These nanoparticles have been shown to recognize
anions via changes in the absorbance spectrum of the surface adsorbed porphyrin moieties. Association constants, derived from
quantitative titrations, indicate a remarkable surface enhancement effect where the surface bound porphyrins bind anions much
more strongly than the free receptor in solution. 相似文献
19.
20.
“空中B超”——遥感影像用于考古 总被引:1,自引:0,他引:1
结合全球卫星定位系统GPS,遥感成像技术能提供大量对考古研究极为有价值的田野影像信息。结合不同年代拍摄的航空照片,考古学家从这些遥感影像中获得大量信息,并得以在近些年来取得很多举世瞩目的成果。本文列举了一系列典型事例,也披露了我国一些古迹的演变情况。 相似文献