全文获取类型
收费全文 | 27041篇 |
免费 | 1294篇 |
国内免费 | 1402篇 |
专业分类
电工技术 | 1385篇 |
技术理论 | 1篇 |
综合类 | 1544篇 |
化学工业 | 1791篇 |
金属工艺 | 1131篇 |
机械仪表 | 3481篇 |
建筑科学 | 1708篇 |
矿业工程 | 595篇 |
能源动力 | 1067篇 |
轻工业 | 699篇 |
水利工程 | 620篇 |
石油天然气 | 673篇 |
武器工业 | 230篇 |
无线电 | 1907篇 |
一般工业技术 | 1119篇 |
冶金工业 | 795篇 |
原子能技术 | 400篇 |
自动化技术 | 10591篇 |
出版年
2024年 | 36篇 |
2023年 | 161篇 |
2022年 | 285篇 |
2021年 | 420篇 |
2020年 | 392篇 |
2019年 | 335篇 |
2018年 | 358篇 |
2017年 | 469篇 |
2016年 | 615篇 |
2015年 | 738篇 |
2014年 | 1397篇 |
2013年 | 1352篇 |
2012年 | 1543篇 |
2011年 | 2139篇 |
2010年 | 1502篇 |
2009年 | 1448篇 |
2008年 | 1484篇 |
2007年 | 1972篇 |
2006年 | 1933篇 |
2005年 | 1767篇 |
2004年 | 1477篇 |
2003年 | 1484篇 |
2002年 | 1165篇 |
2001年 | 884篇 |
2000年 | 663篇 |
1999年 | 711篇 |
1998年 | 582篇 |
1997年 | 472篇 |
1996年 | 381篇 |
1995年 | 352篇 |
1994年 | 252篇 |
1993年 | 186篇 |
1992年 | 160篇 |
1991年 | 110篇 |
1990年 | 100篇 |
1989年 | 91篇 |
1988年 | 77篇 |
1987年 | 31篇 |
1986年 | 31篇 |
1985年 | 39篇 |
1984年 | 34篇 |
1983年 | 18篇 |
1982年 | 24篇 |
1981年 | 16篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 14篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
本文介绍了分站式系统、无分站式系统以及复全式系统的特点,主要论述了复合式微机安全生产监测监控的结构、性能和应用。 相似文献
84.
Gabriele Pannocchia Author Vitae Author Vitae Stephen J. Wright Author Vitae 《Automatica》2007,43(5):852-860
Partial enumeration (PE) is presented as a method for treating large, linear model predictive control applications that are out of reach with available MPC methods. PE uses both a table storage method and online optimization to achieve this goal. Versions of PE are shown to be closed-loop stable. PE is applied to an industrial example with more than 250 states, 32 inputs, and a 25-sample control horizon. The performance is less than 0.01% suboptimal, with average speedup factors in the range of 80-220, and worst-case speedups in the range of 4.9-39.2, compared to an existing MPC method. Small tables with only 25-200 entries were used to obtain this performance, while full enumeration is intractable for this example. 相似文献
85.
In this paper a discrete dynamic model of a single workstation is used to design and analyse control algorithms for closed-loop PPC that improve performance, especially response to disturbances such as rush orders and periodic fluctuations in capacity, while ensuring that dynamic behavior remains favorable and robust. The presence of delays in adjusting capacity presents challenges in both dynamic analysis and control algorithm design that are addressed in the paper. Methods of control engineering, such as transfer function and frequency response analysis, are used to make analysis of fundamental system properties tractable and to improve control of dynamic behavior. 相似文献
86.
Isothermal melt spinning experiments have been conducted using two polyethylene melts of low density (LDPE) and high density
(HDPE) to produce steady state spinline profiles. The data revealed the threadline extensional viscosity exhibiting a contrasting
picture : extension thickening behavior for LDPE and extension thinning one for HDPE. A White-Metzner model having a strain
rate-dependent relaxation time was then found to be able to simulate this dichotomy in melt spinning fairly well: the fluids
whose relaxation times have smaller strain rate-dependence can fit LDPE data with extension thickening extensional viscosity
whereas the fluids whose relaxation times have larger strain rate-dependence can fit HDPE data with extension thinning extensional
viscosity. This dichotomous nature of viscoelastic fluids is also believed to be able to explain other similar contrasting
phenomena exhibited by polymer melts, such as vortex/no vortex in entry flows, cohesive/ductile fracture modes in extension,
and more/less stable draw resonance than Newtonian fluids. 相似文献
87.
下运带式输送机液压制动系统的研究 总被引:7,自引:0,他引:7
首先对下运带式输送机的制动问题进行了分析,而后介绍了一种新型液压制动系统的基本原理、组成和用途,以及液压制动系统的控制要求和工作状态。实践结果表明,采用该液压制动系统从根本上保证了大倾角下运带式输送机的安全高效生产。 相似文献
88.
89.
本文基于自回归滑动平均(ARMAX)控制模型的简要介绍,利用混合信号ISPFLASH微控制器技术,详细介绍了车辆行驶动态过程的空燃比自校正控制(STC)的硬件结构和软件配置及设计方法。 相似文献
90.
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