全文获取类型
收费全文 | 450608篇 |
免费 | 38097篇 |
国内免费 | 21177篇 |
专业分类
电工技术 | 28829篇 |
技术理论 | 75篇 |
综合类 | 55093篇 |
化学工业 | 52835篇 |
金属工艺 | 18240篇 |
机械仪表 | 24190篇 |
建筑科学 | 62448篇 |
矿业工程 | 25186篇 |
能源动力 | 15058篇 |
轻工业 | 29474篇 |
水利工程 | 21948篇 |
石油天然气 | 21151篇 |
武器工业 | 5178篇 |
无线电 | 29717篇 |
一般工业技术 | 33001篇 |
冶金工业 | 25043篇 |
原子能技术 | 4035篇 |
自动化技术 | 58381篇 |
出版年
2024年 | 1705篇 |
2023年 | 5111篇 |
2022年 | 9710篇 |
2021年 | 12280篇 |
2020年 | 12437篇 |
2019年 | 9729篇 |
2018年 | 9305篇 |
2017年 | 11384篇 |
2016年 | 13781篇 |
2015年 | 15166篇 |
2014年 | 27950篇 |
2013年 | 24943篇 |
2012年 | 31103篇 |
2011年 | 33560篇 |
2010年 | 25763篇 |
2009年 | 26488篇 |
2008年 | 24564篇 |
2007年 | 31117篇 |
2006年 | 28940篇 |
2005年 | 25323篇 |
2004年 | 21403篇 |
2003年 | 19022篇 |
2002年 | 15599篇 |
2001年 | 13076篇 |
2000年 | 11043篇 |
1999年 | 8861篇 |
1998年 | 6582篇 |
1997年 | 5756篇 |
1996年 | 5086篇 |
1995年 | 4272篇 |
1994年 | 3746篇 |
1993年 | 2774篇 |
1992年 | 2393篇 |
1991年 | 1744篇 |
1990年 | 1524篇 |
1989年 | 1364篇 |
1988年 | 1001篇 |
1987年 | 698篇 |
1986年 | 544篇 |
1985年 | 499篇 |
1984年 | 435篇 |
1983年 | 338篇 |
1982年 | 267篇 |
1981年 | 224篇 |
1980年 | 191篇 |
1979年 | 135篇 |
1978年 | 83篇 |
1977年 | 90篇 |
1976年 | 66篇 |
1975年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 152 毫秒
91.
Reliability based criteria are quite popular for optimal sensor network design. We present a modified definition of system reliability for sensor network design for two applications: reliable estimation of variables in a steady state linear flow process, and reliable fault detection and diagnosis for any process. Unlike the weakest-link based definition of system reliability in the literature, the proposed definition considers the entire system and is consistent with the reliability concept used in classical reliability literature. For each application, dual approaches for defining system reliability are proposed, and their analogy with the reliability problem in the classical reliability literature is established. Using examples and stochastic simulations, the advantage of using the proposed system reliability in contrast to the existing definition is illustrated. Part II of this series of articles presents methods for efficient generation of the system reliability function and its use in optimization-based approaches for designing optimal sensor networks. 相似文献
92.
Fault detection and isolation in water distribution networks is an active topic due to the nonlinearities of flow propagation and recent increases in data availability due to sensor deployment. Here, we propose an efficient two-step data driven alternative: first, we perform sensor placement taking the network topology into account; second, we use incoming sensor data to build a network model through online dictionary learning. Online learning is fast and allows tackling large networks as it processes small batches of signals at a time. This brings the benefit of continuous integration of new data into the existing network model, either in the beginning for training or in production when new data samples are gathered. The proposed algorithms show good performance in our simulations on both small and large-scale networks. 相似文献
93.
文章通过对黑龙江省高效节水现状,存在问题的分析,结合黑龙江省高效节水发展的支撑能力,阐述黑龙江省节水增粮目标、任务及总体布局,为黑龙江省2012—2015年节水增粮实施提供依据。 相似文献
94.
Robert Brooke Manrico Fabretto Samuel Pering Eliza Switalska Lachlan Reeks Drew Evans Peter Murphy 《应用聚合物科学杂志》2015,132(26)
A study using three different pairs of electrochromic polymers (ECPs) synthesized onto plaques by means of a modified vapor phase polymerization (VPP) technique is presented. Restriction of the respective polymerization times, allowed both faster and slower polymerizing monomers to be controlled, and produced blended plaques with visually diffuse interfaces. The ECPs within the blended plaques retain their individual electrochromic behavior and when encapsulated into an electrochromic device, show outstanding optical switching performance with little degradation evident over 10,000 cycles, coupled with a switching time of the order of 1 second. Blends also allow multiple diffuse color changes within an electrochromic device, due to the difference in oxidation potentials of the individual ECPs, making them candidates for adaptive camouflage use. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42158. 相似文献
95.
96.
Controllability and observability of multi-agent systems with heterogeneous and switching topologies
ABSTRACTThis paper focuses on controllability and observability of multi-agent systems with heterogeneous and switching topologies, where the first- and the second-order information interaction topologies are different and switching. First, based on the controllable state set, a controllability criterion is obtained in terms of the controllability matrix corresponding to the switching sequence. Next, by virtue of the subspace sequence, two necessary and sufficient algebraic conditions are established for controllability in terms of the system matrices corresponding to all the possible topologies. Furthermore, controllability is considered from the graphic perspective. It is proved that the system is controllable if the union graph of all the possible topologies is controllable. With respect to observability, two sufficient and necessary conditions are derived by taking advantage of the system matrices and the corresponding invariant subspace, respectively. Finally, some simulation examples are worked out to illustrate the theoretical results. 相似文献
97.
与传统比例-积分-微分(PID)控制方法相比,滑模控制(SMC)方法可以比较容易地将不确定性纳入控制器设计中,从而增强系统的鲁棒性。探索了SMC技术在运载器主动段姿态控制中的工程应用,首先通过分析基于趋近律的SMC系统,提出了降低不连续切换项系数的需求,然后研究了基于干扰上界的SMC方法。三通道小偏差仿真结果验证了两种方法的控制效果,表明第2种控制器的鲁棒性更好,稳态误差小,同时发动机喷管摆角需求较小。 相似文献
98.
泛在电力物联网是物联网在电力领域的具体体现,建设泛在电力物联网是推进"三型两网"建设的关键环节,也是实现能源转型的必要手段。阐述了泛在电力物联网的定义,从供电公司角度出发,根据北京经济技术开发区实际情况,讨论了依托地区特点的泛在电力物联网实施策略和实际应用场景,分析了可能遇到的问题。得出结论:随着泛在电力物联网的深入建设,供电公司能够为电力客户提供多元化服务,提高客户满意度;地市供电公司能够依托泛在电力物联网开展更多电力相关业务;泛在电力物联网的安全性、实用性、有效性是发展面临的首要问题。 相似文献
99.
100.
ABSTRACTIn this paper, we review some algebraic control system. Precisely, linear and bilinear systems on Euclidean spaces and invariant and linear systems on Lie groups. The fourth classes of systems have a common issue: to any class, there exists an associated subgroup. From this object, we survey the controllability property. Especially, from those coming from our contribution to the theory. 相似文献