全文获取类型
收费全文 | 74358篇 |
免费 | 10310篇 |
国内免费 | 7534篇 |
专业分类
电工技术 | 5649篇 |
技术理论 | 9篇 |
综合类 | 8552篇 |
化学工业 | 2201篇 |
金属工艺 | 1481篇 |
机械仪表 | 4498篇 |
建筑科学 | 4434篇 |
矿业工程 | 1956篇 |
能源动力 | 1286篇 |
轻工业 | 1056篇 |
水利工程 | 1635篇 |
石油天然气 | 3098篇 |
武器工业 | 954篇 |
无线电 | 11225篇 |
一般工业技术 | 4621篇 |
冶金工业 | 1316篇 |
原子能技术 | 789篇 |
自动化技术 | 37442篇 |
出版年
2024年 | 202篇 |
2023年 | 1214篇 |
2022年 | 2354篇 |
2021年 | 2850篇 |
2020年 | 2822篇 |
2019年 | 2208篇 |
2018年 | 2048篇 |
2017年 | 2485篇 |
2016年 | 2774篇 |
2015年 | 3212篇 |
2014年 | 4986篇 |
2013年 | 4635篇 |
2012年 | 5513篇 |
2011年 | 5916篇 |
2010年 | 4573篇 |
2009年 | 4552篇 |
2008年 | 5123篇 |
2007年 | 5750篇 |
2006年 | 4939篇 |
2005年 | 4416篇 |
2004年 | 3748篇 |
2003年 | 3119篇 |
2002年 | 2425篇 |
2001年 | 1911篇 |
2000年 | 1590篇 |
1999年 | 1221篇 |
1998年 | 974篇 |
1997年 | 834篇 |
1996年 | 655篇 |
1995年 | 592篇 |
1994年 | 478篇 |
1993年 | 342篇 |
1992年 | 253篇 |
1991年 | 247篇 |
1990年 | 195篇 |
1989年 | 157篇 |
1988年 | 132篇 |
1987年 | 84篇 |
1986年 | 70篇 |
1985年 | 102篇 |
1984年 | 79篇 |
1983年 | 81篇 |
1982年 | 75篇 |
1981年 | 47篇 |
1980年 | 36篇 |
1979年 | 39篇 |
1978年 | 18篇 |
1977年 | 24篇 |
1976年 | 19篇 |
1975年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
文章首先总结了电力企业信息管理系统的现状,提出了多源信息管理系统融合集成的邦联、子集和完全融合3种方式,分析了3种方式的优缺点,以建设企业"互联网搜索"型数字引擎为目标,提出了融合基于本体的图数据库建模,多维关联与路径因果分析,和人机共生互动可视化决策于一体的企业信息管理系统技术发展趋势;在系统分析目前正在快速发展的图数据库技术与传统关系数据库之间的本质区别基础上,总结原创的电力图计算平台技术的特点;在此基础上讨论"电网一张图"在建设能源互联网时空信息管理平台数据关联索引图中的核心作用,提出了支持能源互联网建设的"电网一张图"时空信息管理系统的技术架构与特点,最后总结"电网一张图"时空信息管理系统在提高电网安全运行水平、提升客户服务水平、增强清洁能源消纳水平、改善经营绩效水平、以及为综合能源服务和建设能源生态等提供数据服务方面的广阔应用场景。 相似文献
42.
Learning Association Rules and Tracking the Changing Concepts on Webpages: An Effective Pornographic Websites Filtering Approach 下载免费PDF全文
Jyh-Jian Sheu 《电子科技学刊:英文版》2018,16(1):24-36
We applied the decision tree algorithm to learn association rules between webpage’s category (pornographic or normal) and the critical features. Based on these rules, we proposed an efficient method of filtering pornographic webpages with the following major advantages: 1) a weighted window-based technique was proposed to estimate for the condition of concept drift for the keywords found recently in pornographic webpages; 2) checking only contexts of webpages without scanning pictures; 3) an incremental learning mechanism was designed to incrementally update the pornographic keyword database. 相似文献
43.
44.
基于SSM框架的大坝监测数据管理系统设计 总被引:1,自引:0,他引:1
针对目前大坝安全监测存在数据不能实时计算分析、展示,长期运行产生的大量数据主要靠人工整编且易出错等问题,结合现代信息化技术手段,以Java作为服务开发语言,设计了基于Spring+SpringMVC+Mybatis(SSM)框架的大坝安全监测数据管理平台,用于大坝监测数据的管理和分析,实现数据采集、存储、查询、计算分析、绘图、生成报表报告、实时监控及远程展示等功能,同时亦为监测仪器管理提供了可视化界面,方便仪器管理。结果表明,基于SSM框架的大坝安全监测数据管理系统实时反馈效果好,操作便捷,数据存取性能好、可视化程度高,便于大坝监测数据的管理与实时分析,为大坝安全运行与决策提供支撑。 相似文献
45.
We define the emerging research field of applied data science as the knowledge discovery process in which analytic systems are designed and evaluated to improve the daily practices of domain experts. We investigate adaptive analytic systems as a novel research perspective of the three intertwining aspects within the knowledge discovery process in healthcare: domain and data understanding for physician- and patient-centric healthcare, data preprocessing and modelling using natural language processing and (big) data analytic techniques, and model evaluation and knowledge deployment through information infrastructures. We align these knowledge discovery aspects with the design science research steps of problem investigation, treatment design, and treatment validation, respectively. We note that the adaptive component in healthcare system prototypes may translate to data-driven personalisation aspects including personalised medicine. We explore how applied data science for patient-centric healthcare can thus empower physicians and patients to more effectively and efficiently improve healthcare. We propose meta-algorithmic modelling as a solution-oriented design science research framework in alignment with the knowledge discovery process to address the three key dilemmas in the emerging “post-algorithmic era” of data science: depth versus breadth, selection versus configuration, and accuracy versus transparency. 相似文献
46.
C语言作为一种程序设计语言,在大数据组成的物联网和云计算中应用广泛,具有强大的适应性和兼容性,是大数据时代下,在IT行业中起到关键作用的程序设计语言。文章分析了基于大数据的C语言程序设计的必然性和应用策略,为C语言在大数据上的应用方向提供了参考依据。以汉字的应用为例,提出了解决C语言应用问题的思路。 相似文献
47.
为了降低机床等待过程中的能耗,提出了一种实时数据驱动的机床等待时间预测与节能控制方法。首先,建立了射频识别驱动的生产进度评估方法,并以生产进度数据作为输入,构建了基于堆栈降噪自编码的机床等待时间预测模型;其次,依据预测的机床等待时间,提出了机床状态切换方法,以降低机床能耗;最后,通过一个电梯零部件制造车间的案例分析,表明该方法的预测误差仅为4.1%,同时将机床等待过程能耗降低了57%,实现了制造车间的节能减排。 相似文献
48.
Bayar Mohammed Rayya Hassan Nahla Alaswadko 《International Journal of Pavement Engineering》2018,19(12):1096-1110
The purpose of this study is to assess the effect of traffic data source (estimated vs. actual) on predicted progression rates of roughness and rutting for heavy-duty flexible pavements of rural freeways. Progression rates are predicted using calibrated HDM-4 models. The assessment is performed in terms of variations in maintenance intervention timing associated with the variations in progression rates. Time series pavement condition data (covering 3–5 years) have been collected for 7 sections of rural freeways for use in calibrating HDM-4 deterioration models. They range in length from 10 to 60.8 km and cover different traffic volumes, climate zones and subgrade soil types. For these sections, estimated annual average daily traffic (AADT), growth factors and assumed loading have been extracted from relevant database. Only six segments of these sections have Weigh-in-Motion (WIM) sites so relevant actual AADT, growth factors and axle load distributions have been extracted from WIM reports. The results of running the calibrated HDM-4 deterioration models using different traffic data show that actual traffic data from WIM sites result in higher rates of deterioration to that of estimated data for four sites, resulting in earlier intervention timing and higher present value agency cost. The other two sites have lower rates with actual data due to lower traffic loading than estimated. 相似文献
49.
Meimei Xia Jian Chen Xiao‐Jun Zeng 《International Transactions in Operational Research》2020,27(2):1080-1100
Existing approaches to data envelopment analysis focus mainly on the derivation of the efficiency of the individual decision‐making unit (DMU) or on the calculation of the weights of multiple inputs or outputs, but pay little attention to the team interest of all the DMUs. Motivated by the idea of team reasoning, in which the benefit of the team is of higher importance than that of each individual, this paper considers all the DMUs as a team and introduces the team indexes including the overall efficiencies, variance, boundaries of all the DMUs, and relationships between DMUs. Several models are first developed to estimate values of the team indexes based on which decision makers can provide their preferences regarding them. Then, models are established to obtain the interval efficiencies of individual DMUs under the condition that the team indexes are satisfied. Several examples are given to illustrate the proposed approaches and verify their applicability. 相似文献
50.