全文获取类型
收费全文 | 4377篇 |
免费 | 203篇 |
国内免费 | 196篇 |
专业分类
电工技术 | 265篇 |
综合类 | 236篇 |
化学工业 | 26篇 |
金属工艺 | 55篇 |
机械仪表 | 360篇 |
建筑科学 | 205篇 |
矿业工程 | 40篇 |
能源动力 | 24篇 |
轻工业 | 44篇 |
水利工程 | 14篇 |
石油天然气 | 15篇 |
武器工业 | 53篇 |
无线电 | 976篇 |
一般工业技术 | 76篇 |
冶金工业 | 81篇 |
原子能技术 | 16篇 |
自动化技术 | 2290篇 |
出版年
2024年 | 2篇 |
2023年 | 19篇 |
2022年 | 26篇 |
2021年 | 37篇 |
2020年 | 60篇 |
2019年 | 33篇 |
2018年 | 48篇 |
2017年 | 55篇 |
2016年 | 72篇 |
2015年 | 86篇 |
2014年 | 209篇 |
2013年 | 156篇 |
2012年 | 254篇 |
2011年 | 311篇 |
2010年 | 213篇 |
2009年 | 207篇 |
2008年 | 229篇 |
2007年 | 357篇 |
2006年 | 295篇 |
2005年 | 313篇 |
2004年 | 268篇 |
2003年 | 260篇 |
2002年 | 215篇 |
2001年 | 161篇 |
2000年 | 117篇 |
1999年 | 135篇 |
1998年 | 122篇 |
1997年 | 93篇 |
1996年 | 80篇 |
1995年 | 63篇 |
1994年 | 43篇 |
1993年 | 52篇 |
1992年 | 34篇 |
1991年 | 27篇 |
1990年 | 26篇 |
1989年 | 28篇 |
1988年 | 14篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1975年 | 9篇 |
1974年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有4776条查询结果,搜索用时 531 毫秒
141.
142.
143.
144.
Fault-tolerant scheduling is an imperative step for large-scale computational Grid systems, as often geographically distributed nodes co-operate to execute a task. By and large, primary-backup approach is a common methodology used for fault tolerance wherein each task has a primary and a backup on two different processors. In this paper, we address the problem of how to schedule DAGs in Grids with communication delays so that service failures can be avoided in the presence of processors faults. The challenge is, that as tasks in a DAG have dependence on each other, a task must be scheduled to make sure that it will succeed when any of its predecessors fails due to a processor failure. We first propose a communication model and determine when communications between a backup and backups of its successors are necessary. Then we determine when a backup can start and its eligible processors so as to guarantee that every DAG can complete upon any processor failure. We develop two algorithms to schedule backups, which minimize response time and replication cost, respectively. We also develop a suboptimal algorithm which targets minimizing replication cost while not affecting response time. We conduct extensive simulation experiments to quantify the performance of the proposed algorithms. 相似文献
145.
Marcela D. Rodríguez Victor M. Gonzalez Jesus Favela Pedro C. Santana 《Computers in human behavior》2009
As in many Latin–American countries, in Mexico many older adults live alone as a result of the migration of one or more of their relatives, mostly to the USA. Thus, not only do they live alone, but they might seldom see these relatives for long periods, even though they often depend on them financially. With the goal of designing appropriate communication technology for seniors and their relatives experiencing this situation, we conducted interviews and evaluated scenarios and prototypes to reveal the practical ways they maintain emotional ties despite the distance. Based on those findings, we envisioned a communication system through which seniors and their relatives can maintain close social ties by sharing information, personal reminiscences and stories. We found that older adults perceived the system as a richer, natural form of communication with their relatives that could facilitate their integration into the networks that currently connect members of their families. 相似文献
146.
在西门子S7—200PLC系统中,通常所配置的人机界面大多采用西门子专用的TP170、TP27、OP37等系列触摸屏。一旦这些触摸屏发生故障和损坏,难以采购和维修,且备件成本较高。本案例采用当今流行的通用PC机来代替TP27和OP37等专用HMI设备,并实现了PC机与S7—200PLC之间的数据通信,为PLC系统触摸屏的通用化改造提供了一个应用实例。 相似文献
147.
148.
This paper introduces a control strategy based on retuning a multi-rate PID controller in accordance with the variable delays detected in a networked control system, in order to avoid a decreased control performance. The basic idea is minimising the first-order Taylor terms of a performance measure via gain scheduling, i.e., making the controller gains delay dependent. As network delay is time-variant, the stability of this control approach will be proved by means of linear matrix inequalities. 相似文献
149.
This paper studies the H∞ filtering problem for networked discrete-time systems with random packet losses. The general multiple-input-multiple-output (MIMO) filtering system is considered. The multiple measurements are transmitted to the remote filter via distinct communication channels, and each measurement loss process is described by a two-state Markov chain. Both the mode-independent and the mode-dependent filters are considered, and the resulting filtering error system is modelled as a discrete-time Markovian system with multiple modes. A necessary and sufficient condition is derived for the filtering error system to be mean-square exponentially stable and achieve a prescribed H∞ noise attenuation performance. The obtained condition implicitly establishes a relation between the packet loss probability and two parameters, namely, the exponential decay rate of the filtering error system and the H∞ noise attenuation level. A convex optimization problem is formulated to design the desired filters with minimized H∞ noise attenuation level bound. Finally, an illustrative example is given to show the effectiveness of the proposed results. 相似文献
150.