全文获取类型
收费全文 | 20870篇 |
免费 | 1924篇 |
国内免费 | 1761篇 |
专业分类
电工技术 | 892篇 |
综合类 | 2038篇 |
化学工业 | 1462篇 |
金属工艺 | 931篇 |
机械仪表 | 1195篇 |
建筑科学 | 1971篇 |
矿业工程 | 264篇 |
能源动力 | 389篇 |
轻工业 | 297篇 |
水利工程 | 249篇 |
石油天然气 | 338篇 |
武器工业 | 207篇 |
无线电 | 4435篇 |
一般工业技术 | 1679篇 |
冶金工业 | 306篇 |
原子能技术 | 697篇 |
自动化技术 | 7205篇 |
出版年
2024年 | 79篇 |
2023年 | 201篇 |
2022年 | 379篇 |
2021年 | 484篇 |
2020年 | 475篇 |
2019年 | 446篇 |
2018年 | 448篇 |
2017年 | 629篇 |
2016年 | 668篇 |
2015年 | 782篇 |
2014年 | 1216篇 |
2013年 | 1391篇 |
2012年 | 1424篇 |
2011年 | 1651篇 |
2010年 | 1196篇 |
2009年 | 1366篇 |
2008年 | 1302篇 |
2007年 | 1497篇 |
2006年 | 1392篇 |
2005年 | 1163篇 |
2004年 | 991篇 |
2003年 | 931篇 |
2002年 | 740篇 |
2001年 | 524篇 |
2000年 | 470篇 |
1999年 | 419篇 |
1998年 | 404篇 |
1997年 | 288篇 |
1996年 | 252篇 |
1995年 | 221篇 |
1994年 | 197篇 |
1993年 | 151篇 |
1992年 | 109篇 |
1991年 | 109篇 |
1990年 | 78篇 |
1989年 | 80篇 |
1988年 | 60篇 |
1987年 | 36篇 |
1986年 | 51篇 |
1985年 | 48篇 |
1984年 | 44篇 |
1983年 | 30篇 |
1982年 | 30篇 |
1981年 | 20篇 |
1980年 | 27篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1973年 | 3篇 |
1959年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Jing Yuan Yury Stepanenko 《International Journal of Adaptive Control and Signal Processing》1992,6(2):111-126
A new adaptive controller is presented here for rigid-body robotic manipulators. It is stable and robust with respect to a class of external disturbances. The robustness of the adaptive controller is established without the ‘slow-varying’ assumption and the computationally demanding regressor matrix. The control law consists of a non-adaptive PD control part and an adaptive control part. It uses two adaptive matrices to compensate two uniformly bounded coefficient matrices derived from the original dynamics. A α σ|q?|-modified adaptive law is designed to adjust the adaptive matrices. A Lyapunov-type stability analysis indicates that the closed-loop system is uniformly ultimately bounded. The tracking error and compensation error will eventually converge into a closed region, which can be made arbitrarily small by adjusting the controller parameters. Simulation results are included to demonstrate the performance of the proposed controller. 相似文献
93.
A system-on-chip (SOC) usually consists of many memory cores with different sizes and functionality, and they typically represent a significant portion of the SOC and therefore dominate its yield. Diagnostics for yield enhancement of the memory cores thus is a very important issue. In this paper we present two data compression techniques that can be used to speed up the transmission of diagnostic data from the embedded RAM built-in self-test (BIST) circuit that has diagnostic support to the external tester. The proposed syndrome-accumulation approach compresses the faulty-cell address and March syndrome to about 28% of the original size on average under the March-17N diagnostic test algorithm. The key component of the compressor is a novel syndrome-accumulation circuit, which can be realized by a content-addressable memory. Experimental results show that the area overhead is about 0.9% for a 1Mb SRAM with 164 faults. A tree-based compression technique for word-oriented memories is also presented. By using a simplified Huffman coding scheme and partitioning each 256-bit Hamming syndrome into fixed-size symbols, the average compression ratio (size of original data to that of compressed data) is about 10, assuming 16-bit symbols. Also, the additional hardware to implement the tree-based compressor is very small. The proposed compression techniques effectively reduce the memory diagnosis time as well as the tester storage requirement. 相似文献
94.
曙—区超稠油间歇蒸汽吞吐技术探讨 总被引:3,自引:1,他引:2
针对曙-区超稠油井进入高周期后产量递减,成本上升的矛盾,提出用间歇吞吐技术改善高周期蒸汽吞吐效果,通过对吞吐机理和现场实际资料统计的分析。对这项技术实施的条件及效果进行了探讨。结果表明,该项技术在高周期井实施效果较好。具有较好的推广前景。 相似文献
95.
The research literature has seen a number of studies aimed at understanding customer attitudes towards banking technologies, and thereby providing implications for developmental planning and marketing. However, even though banking technologies have a significant amount of information systems (IS) component to them, there is a paucity of research that considers them from the IS perspective. In this paper, we fill this gap by considering three constructs, namely usefulness, ease of use and usage, that are all rooted in the IS literature. We study user’s perceptions of these constructs, as well as the relationships among them, for both online and telephone banking. 相似文献
96.
本文介绍了配电电力地理信息系统外业数据采集编码的方法;其中包括线路编码、点编码、线路分界点编码、变电所的编码、开关的编码方法等。 相似文献
97.
BINELOCA程序是在吸收国外先进大破口失水事故分析计算机程序的基础上,针对我国现有大破口失水事故分析程序的不足和工程应用方面的问题,采用了一些成熟的、新型的和当今国际公认的瞬态热工水力数学物理模型以及水和蒸汽性质参数计算公式改编而成的大破口失水事故分析程序。通过对广东岭澳核电站大破口失水事故的计算表明,BINELOCA程序计算的结果与法国计算的结果是一致的。 相似文献
98.
在线误码监测方法及其性能 总被引:1,自引:0,他引:1
本文论述了在数字通信中进行在线误码监测的必要性,介绍了几种在线误码监测方法,并对其监测性能进行了理论分析。 相似文献
99.
P. Chen D. Cline W. Craddock F.J. Decker R. Iverson T. Katsouleas P. Kwok W. Leemans S. Masuda D.D. Meyerhofer K. Nakajima A. Ogata P. Raimondi A. Sessler D. Walz A. Weidemann 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1998,410(3):407-417
The proposed plasma lens experiment at the Final focus Test Beam (FFTB) facility of the Stanford Linear Accelerator Center has been approved by the adminstration. The experiment would allow the examination of plasma focusing devices for particle beams in the parameter regime of interest to future high-energy colliders. It is expected to lead to compact plasma lens designs capable of focusing the beam to unprecedented small spot sizes. 相似文献
100.
P. Adaikkalam N. Sathaiyan S. Visvanathan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1993,56(4):389-392
Cyclic voltammetric and galvanostatic experiments have been carried out with both synthetic and commercial bleach solutions with a view to regenerating the same. Maximum efficiency could be achieved if the oxidation is carried out below an anodic potential of 0·80 V vs SCE. The data obtained in galvanostatic experiments with RCE confirm the results of the earlier technique. 相似文献