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Nonintrusive load monitoring (NILM) is crucial for extracting patterns of electricity consumption of household appliance that can guide users’ behavior in using electricity while their privacy is respected. This study proposes an online method based on the transient behavior of individual appliances as well as system steady-state characteristics to estimate the operating states of the appliances. It determines the number of states for each appliance using the density-based spatial clustering of applications with noise (DBSCAN) method and models the transition relationship among different states. The states of the working appliances are identified from aggregated power signals using the Kalman filtering method in the factorial hidden Markov model (FHMM). Thereafter, the identified states are confirmed by the verification of system states, which are the combination of the working states of individual appliances. The verification step involves comparing the total measured power consumption with the total estimated power consumption. The use of transient features can achieve fast state inference and it is suitable for online load disaggregation. The proposed method was tested on a high-resolution data set such as Labeled hIgh-Frequency daTaset for Electricity Disaggregation (LIFTED) and it outperformed other related methods in the literature. 相似文献
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提出了一种变电站集中保护方案( CPS ),该方案对变电站内的保护系统进行监控,检测隐性故障,提高保护系统的安全性。该监控通过实时动态状态估计来实现。该方法支持系统内的智能电子设备( IED )向 CPS 传输数据,通过 CPS 处理数据、检测异常并进行动态状态估计。在使用卡方检验检测到异常后,通过假设检验,将问题归类为隐性故障或电源故障。若检测到隐性故障则触发闭锁信号,以保护受影响的智能电子设备免受误动作。所提出的架构为智能变电站提供一种可靠的数据管理技术和通信系统的优化手段。 相似文献
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火灾自动报警系统是现代建筑中较为常见的建筑消防设施,本文通过总结火灾自动报警系统的消防监督检查经验,深入研究其隐患类型、分布特点及查找方式,形成一套火灾自动报警系统的检查方法。基于多省、市消防监督检查的大量样本数据,开展火灾自动报警系统隐患数量与人均GDP的关联性分析计算。并对检查情况进行系统的统计与分析,发现火灾自动报警系统主要存在消防控制室设备类、现场设备类和系统功能类3大类隐患,分别从初始设计、安装调试、设备选型、维护保养和安全管理5个方面对每类隐患问题进行分析研究并提出合理建议。研究结果可直接应用于我国消防监督管理政策制订、发展规划和日常监督检查工作中,为消防监督检查提供技术支持。 相似文献
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This study focuses on the asynchronous control problem for two‐dimensional discrete‐time hidden Markovian jump systems where the mode observation conditional probability matrix is partly known. Considering the original system modes are invisible, the observed modes emitted from an observer serve as an alternative for stability analysis and controller design where a mode observation conditional probability matrix is constructed to characterize the emission between system modes and observed modes. Specially, only partly known information of the mode observation conditional probability matrix is accessible. With the introduction of the free‐connection weighting matrices, the asymptotic mean square stability criterion is firstly derived based on Lyapunov method. This introduction provides a further degree of relaxation and less conservatism is therefore achieved. Secondly, we present synthesis conditions for asynchronous state feedback controller design given in terms of a set of interconnected linear matrix inequalities. Moreover, cluster concept based on the partitions of observed modes is adopted which helps to decrease the number of controllers and simplify the design complexity. A numerical example, regarding the cases with and without clustering of the observed modes, is presented to illustrate the effectiveness of the proposed method. 相似文献
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Paolo Giudici Iman Abu Hashish 《Quality and Reliability Engineering International》2020,36(6):2057-2065
The objective of this work is to understand the dynamics of cryptocurrency prices. Specifically, how prices switch between different regimes, going from “bull” to “stable” and “bear” times. For this purpose, we propose a hidden Markov model that aims at explaining the evolution of Bitcoin prices through different, unobserved states. The implementation of the proposed model includes a likelihood ratio test that allows to compare models with different states and with different covariance structures. Our empirical findings show that the time movements of Bitcoin prices across different exchange markets are well-described by the proposed model. In particular, a parsimonious model with a diagonal covariance matrix leads to better predictions, compared with a model with a full covariance matrix. 相似文献
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古建筑中宋式斗栱节点最为显著的特征之一就是带有“下昂”。为研究具有这种特征的斗栱节点的受力性能,制作 1∶3.52的缩尺模型试件进行竖向荷载试验和水平低周反复荷载试验,依据宋《营造法式》和实际建筑的 “有昂无梁栿”和“有昂有梁栿”两种类型的宋式斗栱节点模型,设计并制作了以柱头斗栱节点为对象的试验模型。研究结果表明:在竖向荷载作用下,栌斗始终作为薄弱构件首先破坏;下昂与梁栿虽打断了斗栱节点分层叠加,但其依旧能保持良好的整体性;水平荷载作用下单个斗栱节点的倒三角形构造易发生转动,但加入梁栿后,节点的转动受到约束而发生滑移,此时斗栱表现良好的耗能效果,由此说明斗栱节点良好的抗震性能并非来自单个斗栱节点,而是由其通过相互约束协同工作而产生;底部暗销有较强的锚固作用,斗栱节点水平承载力主要由底部暗销的锚固力和柱与斗栱节点接触面的摩擦力组成。 相似文献