全文获取类型
收费全文 | 17248篇 |
免费 | 1786篇 |
国内免费 | 1586篇 |
专业分类
电工技术 | 1454篇 |
技术理论 | 3篇 |
综合类 | 2244篇 |
化学工业 | 385篇 |
金属工艺 | 409篇 |
机械仪表 | 849篇 |
建筑科学 | 1234篇 |
矿业工程 | 310篇 |
能源动力 | 178篇 |
轻工业 | 211篇 |
水利工程 | 348篇 |
石油天然气 | 282篇 |
武器工业 | 93篇 |
无线电 | 3613篇 |
一般工业技术 | 1133篇 |
冶金工业 | 590篇 |
原子能技术 | 30篇 |
自动化技术 | 7254篇 |
出版年
2024年 | 75篇 |
2023年 | 226篇 |
2022年 | 428篇 |
2021年 | 469篇 |
2020年 | 584篇 |
2019年 | 387篇 |
2018年 | 449篇 |
2017年 | 442篇 |
2016年 | 493篇 |
2015年 | 640篇 |
2014年 | 1144篇 |
2013年 | 1150篇 |
2012年 | 1379篇 |
2011年 | 1398篇 |
2010年 | 1116篇 |
2009年 | 1199篇 |
2008年 | 1312篇 |
2007年 | 1426篇 |
2006年 | 1226篇 |
2005年 | 1164篇 |
2004年 | 937篇 |
2003年 | 750篇 |
2002年 | 557篇 |
2001年 | 427篇 |
2000年 | 364篇 |
1999年 | 221篇 |
1998年 | 148篇 |
1997年 | 115篇 |
1996年 | 96篇 |
1995年 | 69篇 |
1994年 | 71篇 |
1993年 | 35篇 |
1992年 | 17篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1973年 | 3篇 |
1958年 | 2篇 |
1957年 | 2篇 |
1956年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
991.
Economic Evaluation of Power System Flexibility by Commercial Air Conditioner Control with Large Penetration of Photovoltaic Generation
下载免费PDF全文
![点击此处可从《Electrical Engineering in Japan》网站下载免费的PDF全文](/ch/ext_images/free.gif)
High penetration of intermittent renewable energy such as photovoltaic (PV) and wind power could cause shortage of power system flexibility. Demand response is expected to help supply ancillary service instead of the conventional power plant. Commercial air conditioners are a promising responsive load for demand response because they account for a large proportion of power consumption in the power system. We calculate a system operation cost and hourly operation pattern of each power plant by using the optimal power generation model considering flexibility supply from controlling commercial air conditioner. We obtained the following results as an effect of commercial air conditioner control. (1) The power generation of oil fired power plants decreases at peak time and annual fuel cost of oil fired plant is reduced by approximately 30% at most in Kanto area. (2) The percentage of rated operation mode of LNG combined cycle plants increases. (3) Curtailed energy rate of PV decreases because a power storage amount by pumped hydropower generation increases. (4) Required battery capacity to reduce PV curtailed amount decreased by combining battery energy storage system in case of high penetration of PV. 相似文献
992.
社区和居家养老是我国当前和未来的主要养老模式,然而,与机构养老设施相比较而言,我国社区居家养老服务设施的发展明显滞后,具体表现为设施的建成基础薄弱、空间资源的配置要素模糊、规范和管控手段缺位等。在概述现状与问题的基础上,系统地探讨了我国社区层面养老服务资源的配置主体、配置对象和配置思路。针对养老服务需求和供给主体日益多元化的挑战,提出结合社区实际情况灵活配置服务模块的建议,采用总量控制和复合设置的规划手段落实配建,从而实现服务设施综合效益最大化的建设目标。 相似文献
993.
994.
杨帆 《吉林化工学院学报》2020,37(10):79-82
近年来,以推进基本公共服务均等化为依托而促进养老等社会服务的发展已成为各省市的重点工作之一,立足于吉林市市情,通过调查研究、定量分析等方式探索本地社区养老存在的问题以及对策。 相似文献
995.
996.
Visualization workflows are important services for expert users to analyze watersheds when using our HydroTerre end-to-end workflows. Analysis is an interactive and iterative process and we demonstrate that the expert user can focus on model results, not data preparation, by using a web application to rapidly create, tune, and calibrate hydrological models anywhere in the continental USA (CONUS). The HydroTerre system captures user interaction for provenance and reproducibility to share modeling strategies with modelers. Our end-to-end workflow consists of four workflows. The first is data workflows using Essential Terrestrial Variables (ETV) data sets that we demonstrated to construct watershed models anywhere in the CONUS (Leonard and Duffy, 2013). The second is data-model workflows that transform the data workflow results to model inputs. The model inputs are consumed in the third workflow, model workflows (Leonard and Duffy, 2014a) that handle distribution of data and model within High Performance Computing (HPC) environments. This article focuses on our fourth workflow, visualization workflows, which consume the first three workflows to form an end-to-end system to create and share hydrological model results efficiently for analysis and peer review. We show how visualization workflows are incorporated into the HydroTerre infrastructure design and demonstrate the efficiency and robustness for an expert modeler to produce, analyze, and share new hydrological models using CONUS national datasets. 相似文献
997.
In order to benefit from operating an IT service platform (e.g., SaaS platform), platform providers need to find a way to keep their existing users and application services active sources of value. However, the understanding of how to achieve that is limited due to the newness of this kind of business. This paper investigates whether all stakeholders of the platform ecosystem can generate sufficient value when participating in the platform. As stakeholders, we consider application service users, service developers, and service platform providers. We also analyse the interrelationship between these stakeholders. The analysis outcome is a value creation model that allows the calculation of the stakeholders’ values. The model also helps inferring the relative impact of different factors on the evolution of values of the software service platform stakeholders. Our simulation results confirm that all stakeholders of a service platform mainly benefit from a growing installed base of application users. However, in a mature market, a large service variety mainly benefits the service platform provider, while the other stakeholders obtain a reduced increase in their benefits. In particular, the utility growth of application users becomes constrained as the benefit from new connections with other users decreases and the number of new services used decreases. Similarly, the revenue of service developer decreases, making service development less profitable. Therefore, we can state that not only a large fraction of the value creation goes to the platform provider but also that the software service ecosystem can collapse, if no mutually beneficial pricing of services is implemented. 相似文献
998.
Journal of Computer Science and Technology - In mobile social networks, next point-of-interest (POI) recommendation is a very important function that can provide personalized location-based... 相似文献
999.
随着医疗服务体系的发展和进步,越来越多的医院开始将云计算技术引入信息服务系统,使医院信息化建设得到了迅速发展。文章分析了云计算技术的特点及其在智能医院信息服务中的应用和影响,以期促进该技术在未来的发展和推广。 相似文献
1000.
William Filisbino Passini Cristiane Aparecida Lana Vinicius Pfeifer Frank Jos Affonso 《Software》2022,52(1):5-38
Self-adaptive service-oriented Applications (Self-Apps) must be able to understand themselves or the environment in which they are executed, and propose solutions to meet changing conditions. The development of these applications is not a trivial task, since it encompasses issues from different research areas. Despite the importance of frameworks for Self-Apps, there is a lack of comprehensive analysis of how the design of such applications is performed, and regarding the standardization of concepts and coverage of minimum requirements for Self-Apps. The main contribution of this article is to present this comprehensive analysis, providing the state of the art for this subject. This analysis was built through a Systematic Mapping Study, based on a total of 65 studies, from which we identify the main attributes for Quality of Service (QoS), search strategies, and service management strategies employed in the design of frameworks for Self-Apps. The main aspects of requirements involved in the design of Self-Apps were pointed out to stakeholders. For example, these applications must implement a method for evaluation of QoS based on metrics. We also put forward the S-Frame, a modular solution that brings together the main features for the design of Self-Apps, and describe the main challenges concerning these applications. 相似文献