全文获取类型
收费全文 | 59403篇 |
免费 | 6708篇 |
国内免费 | 4128篇 |
专业分类
电工技术 | 5497篇 |
综合类 | 6628篇 |
化学工业 | 6033篇 |
金属工艺 | 2152篇 |
机械仪表 | 3340篇 |
建筑科学 | 6061篇 |
矿业工程 | 2515篇 |
能源动力 | 1736篇 |
轻工业 | 3242篇 |
水利工程 | 1754篇 |
石油天然气 | 2504篇 |
武器工业 | 779篇 |
无线电 | 6369篇 |
一般工业技术 | 4961篇 |
冶金工业 | 2761篇 |
原子能技术 | 759篇 |
自动化技术 | 13148篇 |
出版年
2024年 | 208篇 |
2023年 | 658篇 |
2022年 | 1309篇 |
2021年 | 1506篇 |
2020年 | 1787篇 |
2019年 | 1704篇 |
2018年 | 1507篇 |
2017年 | 1973篇 |
2016年 | 2241篇 |
2015年 | 2399篇 |
2014年 | 3511篇 |
2013年 | 3712篇 |
2012年 | 4108篇 |
2011年 | 4442篇 |
2010年 | 3359篇 |
2009年 | 3634篇 |
2008年 | 3385篇 |
2007年 | 4128篇 |
2006年 | 3861篇 |
2005年 | 3289篇 |
2004年 | 2747篇 |
2003年 | 2508篇 |
2002年 | 2132篇 |
2001年 | 1864篇 |
2000年 | 1542篇 |
1999年 | 1236篇 |
1998年 | 946篇 |
1997年 | 865篇 |
1996年 | 677篇 |
1995年 | 582篇 |
1994年 | 471篇 |
1993年 | 365篇 |
1992年 | 273篇 |
1991年 | 239篇 |
1990年 | 171篇 |
1989年 | 150篇 |
1988年 | 105篇 |
1987年 | 116篇 |
1986年 | 64篇 |
1985年 | 65篇 |
1984年 | 60篇 |
1983年 | 44篇 |
1982年 | 37篇 |
1981年 | 34篇 |
1980年 | 37篇 |
1979年 | 29篇 |
1978年 | 13篇 |
1977年 | 14篇 |
1964年 | 13篇 |
1956年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
ZHU Liye FANG Yuan ZHANG Weidong 《机械工程学报(英文版)》2008,21(1):91-93
According to a type of normal nonlinear system, an indirect adaptive fuzzy (IAF) controller has been applied to those systems where no accurate mathematical models of the systems under control are available. To satisfy with system performance, an indirect accelerated adaptive fuzzy (IAAF) controller is proposed, and its general form is presented. The general form IAAF controller ensures necessary control criteria and system's global stability using Lyapunov Theorem. It has been proved that the close-loop system error converges to a small neighborhood of equilibrium point. The optimal IAAF controller is derived to guarantee the process's shortest settling time. Simulation results indicate the IAAF controller make the system more stable, accurate, and fast. 相似文献
102.
张凡 《信息技术与标准化》2006,(12):31-33
介绍了时间戳规范的编制背景和时间戳系统部件组成.时间戳的产生和颁发、时间戳的管理、时间戳的格式和时间戳系统的安全等方面的具体内容。 相似文献
103.
对称配筋小偏心受压构件的截面设计 总被引:4,自引:1,他引:3
对小偏心受压构件在对称配筋情况下的截面配筋计算,提出用最佳一次逼近多项式简化基本公式,直接按二次方程求解ξ的近似方法,具有精度高,相对误差小,计算方便等优点,可供工程设计人员参考。 相似文献
104.
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
105.
Business publications and the popular press have stressed the importance of creating conditions for meaningful employee expression in work roles, also known as engagement. Few empirical studies, however, have examined how individual or situational factors relate to engagement. Consequently, this study examines the interplay between employee age, perceived coworker age composition, and satisfaction with older (older than 55) and younger (younger than 40) coworkers on engagement using a sample of 901 individuals employed in the United Kingdom. Results indicated that satisfaction with one's coworkers related significantly to engagement. Moreover, perceived age similarity was associated with higher levels of engagement among older workers when they were highly satisfied with their coworkers over 55 and lower levels of engagement when they were not. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
106.
道路边坡生态防护初探 总被引:1,自引:0,他引:1
随着我国经济实力的增强和人们环保意识的提高,国家已经十分重视道路建设中的生态建设和环境保护。通过对已建道路边坡防护方式进行分析,找出了存在的问题,提出改善和提高道路边坡防护的方法,并通过工程实例进一步得到验证。 相似文献
107.
This note presents a stabilizing decentralized model predictive control (MPC) algorithm for nonlinear discrete time systems. No information is assumed to be exchanged between local control laws. The stability proof relies on the inclusion of a contractive constraint in the formulation of the MPC problem. 相似文献
108.
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
109.
为了实现利用VisualBasic编程语言实现动画模拟的功能,文章以对运动目标跟踪的计算机模拟为例,提出和实现了用该语言实现动画的各种方法,介绍了每种方法的原理并通过程序示例证明其达到了相应的动画效果。 相似文献
110.
蒋光祖 《上海电机学院学报》2003,6(4):9-10
推导了变压器二次负载电压的计算公式,建议由此公式代替以往原理书中惯用的近似公式。利用此公式绘制和分析了不同功率因数额定负载时的相量轨迹图。 相似文献