全文获取类型
收费全文 | 413篇 |
免费 | 25篇 |
国内免费 | 40篇 |
专业分类
电工技术 | 180篇 |
综合类 | 25篇 |
化学工业 | 11篇 |
机械仪表 | 6篇 |
建筑科学 | 28篇 |
矿业工程 | 1篇 |
能源动力 | 71篇 |
轻工业 | 3篇 |
水利工程 | 44篇 |
石油天然气 | 4篇 |
武器工业 | 1篇 |
无线电 | 43篇 |
一般工业技术 | 12篇 |
冶金工业 | 5篇 |
原子能技术 | 2篇 |
自动化技术 | 42篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 12篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 11篇 |
2016年 | 10篇 |
2015年 | 16篇 |
2014年 | 38篇 |
2013年 | 25篇 |
2012年 | 18篇 |
2011年 | 28篇 |
2010年 | 23篇 |
2009年 | 23篇 |
2008年 | 26篇 |
2007年 | 33篇 |
2006年 | 39篇 |
2005年 | 26篇 |
2004年 | 17篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有478条查询结果,搜索用时 15 毫秒
1.
In many countries, distribution grid tariffs are being reformed to adapt to the new realities of an electricity system with distributed energy resources. In Europe, legislative proposals have been made to harmonize these reforms across country borders. Many stakeholders have argued that distribution tariffs are a local affair, while the European institutions argued that there can be spillovers to other countries, which could justify a more harmonized approach. In this paper, we quantify these spillovers in a simplified numerical example to give insight and an order of magnitude. We look at different scenarios, and find that the spillovers can be both negative and positive. To be able to quantify these effects, we developed a long-run market equilibrium model that captures the wholesale market effects of distribution grid tariffs. The problem is formulated as a non-cooperative game involving consumers, generating companies and distribution system operators in a stylized electricity market. 相似文献
2.
Water tariffs frequently seek to achieve multiple objectives, some of which may conflict. However, the nature and rationale for those conflicts is not always understood or appreciated. This paper consider how localised natural and human phenomena can shape the extent to which so-called ‘best practice’ economic regulation and pricing can be expected to take hold in Victoria and South Australia. Overall, we find that there is room for improvement in the institutional arrangements that circumscribe water pricing in some cases, but direct comparisons are not always helpful, especially when the underlying hydrology, topography and demography of states differs markedly. 相似文献
3.
针对多目标绿色可重入混合流水车间调度问题(RHFSP)的特点,在机器分配和工序排序的基础上引入分时电价机制,构建了以最小化最大完工时间、总能耗成本和碳排放为目标的绿色调度优化模型,提出了一种改进的多目标文化基因算法(MOMA)来求解该问题,通过数值实验验证了所设计的MOMA算法的可行性。实验结果表明MOMA算法在非劣解的收敛性、多样性和支配性指标方面都显著优于多目标蚁狮优化算法(MOALO)、多目标粒子群优化算法(MOPSO)和带精英策略的非支配排序遗传算法(NSGA-Ⅱ),四种算法的分布性指标无显著差异。所提出的模型能够使企业有效避开高电价时段作业,合理转移用电负荷,达到降低总用电成本和碳排放的目的。 相似文献
4.
As the debate on the fairness of water metering continues, the Hotwells metering trial has revealed two new contentious issues which could add credibility to the arguments of those who are opposed to a universal system. One could not have predicted that the safety of electrical appliances would make media headlines on the subject of water metering, or that supporters of rateable value should object to being charged by measured floor area when these two systems are so similar
This paper sets out to concentrate on two particular problems which were encountered during the consultative and installation phases of the Hotwells trial. Whilst the author would not claim to be able to provide definitive answers, he can share the approaches taken by the Company on apportionment and electrical earthing, and highlight I-the most important factors. 相似文献
This paper sets out to concentrate on two particular problems which were encountered during the consultative and installation phases of the Hotwells trial. Whilst the author would not claim to be able to provide definitive answers, he can share the approaches taken by the Company on apportionment and electrical earthing, and highlight I-the most important factors. 相似文献
5.
《Energy Policy》2015
Beginning in 2013, China's photovoltaic (PV) market-development strategy witnessed a series of policy changes aimed at making distributed-generation PV (DG PV) development an equal priority with large-scale PV development. This article reviews the DG PV policy changes since 2013 and examines their effect on China's domestic DG PV market. Based on a 2014 survey of DG PV market and policy participants, we present cost and time breakdowns for installing DG PV projects in China, and we identify the main barriers to DG PV installation. We also use a cash flow model to determine the relative economic attractiveness of DG PV in several eastern provinces in China. The main factors constraining DG PV deployment in China include financial barriers resulting from the structure of the self-consumption feed-in tariff (FIT), ambivalence about DG PV within grid companies, complicated ownership structures for buildings/rooftops/businesses, and the inherent time lag in policy implementation from the central government to provincial and local governments. We conclude with policy implications and suggestions in the context of DG PV policy changes the Chinese government implemented in September 2014. 相似文献
6.
从两个方面对某地市趸售市场及其发展趋势进行了分析,探讨了控股(代管)模式对市场拓展的影响,讨论了控股(代管)模式下趸售市场拓展面临的制约因素,并提出了一些应对策略。 相似文献
7.
This paper presents a residential hybrid thermal/electrical grid-connected home energy system (HES), including a fuel-cell with combined heat and power and a battery-based energy storage system. The minimum operation cost of this integrated energy system is achieved by proper scheduling of different energy resources, found by applying a new powerful optimization algorithm, the Hyper-Spherical Search (HSS) algorithm, to the system's scheduling problem. This is the first time that HSS is used to face the energy resource dispatch problem. The HSS has been only tested in mathematical problems in the previous study. The optimization procedure generates an efficient look-up table in which the powers generated by different energy resources are determined for all time intervals. The effect of different electricity tariffs for purchasing electricity from the main grid on the operation costs of the system is investigated. Moreover, a battery is properly dispatched in the energy system to decrease the operation costs. A real load demand is used in the simulation. The results of HSS are compared with the harmony search algorithm and the colonial competitive algorithm to show the power and effectiveness of HSS to find the optimal dispatch strategy of energy resources for the first time. This is the first time that HSS is compared with CCA. The results of this paper are expected to contribute to home energy systems and real projects. 相似文献
8.
本文通过对英国移动运营商 Everything Ev-erywhere 公司(简称“EE”)的案例研究,从网络、终端、市场策略三个维度进行了问题分析,探寻该企业未能在较长的时间窗口内达到市场预期的原因,并在网络覆盖、终端提供、品牌推广、资费与市场定位、业务等方面总结了对中国移动 LTE 发展的启示。 相似文献
9.
《Energy Policy》2016
This article describes the electricity consumption in Brazilian residences between 1985 and 2013 through linear regressions. The explanatory variables considered were the number of households, effective consumption of families as a proxy for family income, and electricity tariff for households. To deal with the power generation crisis of 2001 we have introduced a dummy variable in the form of a step function. With such explanatory variables, we were able to account for the reduction of household electricity consumption caused by the policies conducted in 2001 and their permanent consequences. The regression presented coefficient of determination of 0.9892, and the several statistic tests conducted assured the existence of long-term relation between the electricity consumption in residences and the explanatory variables. The obtained elasticities for the household consumption of electricity with respect to number of residences, family income and residential tariff of electricity were 1.534±0.095, 0.189±0.049, and −0.230±0.060, respectively. These results allowed understanding the evolution over time of the household consumption of electricity in Brazil. They suggest that the electric sector in Brazil should pursue an active policy to manage demand of residential electricity using tariffs as a means to control it. 相似文献
10.
This study analyzes the effect of governance structure on the tariff levels applied by Brazilian corporations of water supply and sanitation. It aims to contribute to the traditional debate of public versus private management, and to determine the effect of regulatory structure on tariff levels. The results first show that, when jointly considered, the water supply and sanitation tariff levels are higher for privately managed corporations. Second, we have found that a corporation regulated by a local agency or a regional agency does not exhibit significantly lower tariff levels than unregulated corporations. Finally, the results indicate that the use of the rate of return and price cap/revenue cap regimes do not provide tariff levels lower than those set via negotiation with the municipality. 相似文献