全文获取类型
收费全文 | 22229篇 |
免费 | 3290篇 |
国内免费 | 2253篇 |
专业分类
电工技术 | 606篇 |
技术理论 | 2篇 |
综合类 | 2134篇 |
化学工业 | 613篇 |
金属工艺 | 163篇 |
机械仪表 | 405篇 |
建筑科学 | 1499篇 |
矿业工程 | 9490篇 |
能源动力 | 429篇 |
轻工业 | 216篇 |
水利工程 | 258篇 |
石油天然气 | 200篇 |
武器工业 | 44篇 |
无线电 | 961篇 |
一般工业技术 | 565篇 |
冶金工业 | 1550篇 |
原子能技术 | 27篇 |
自动化技术 | 8610篇 |
出版年
2024年 | 61篇 |
2023年 | 216篇 |
2022年 | 554篇 |
2021年 | 802篇 |
2020年 | 969篇 |
2019年 | 641篇 |
2018年 | 638篇 |
2017年 | 678篇 |
2016年 | 803篇 |
2015年 | 867篇 |
2014年 | 1529篇 |
2013年 | 1266篇 |
2012年 | 1988篇 |
2011年 | 1878篇 |
2010年 | 1469篇 |
2009年 | 1611篇 |
2008年 | 1743篇 |
2007年 | 1827篇 |
2006年 | 1610篇 |
2005年 | 1388篇 |
2004年 | 1183篇 |
2003年 | 1118篇 |
2002年 | 714篇 |
2001年 | 513篇 |
2000年 | 432篇 |
1999年 | 305篇 |
1998年 | 229篇 |
1997年 | 140篇 |
1996年 | 128篇 |
1995年 | 113篇 |
1994年 | 102篇 |
1993年 | 76篇 |
1992年 | 53篇 |
1991年 | 46篇 |
1990年 | 15篇 |
1989年 | 13篇 |
1988年 | 16篇 |
1987年 | 14篇 |
1986年 | 5篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1966年 | 1篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1960年 | 3篇 |
1959年 | 1篇 |
1955年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
The paper presents a platform for distributed computing, developed using the latest software technologies and computing paradigms to enable big data mining. The platform, called ClowdFlows, is implemented as a cloud-based web application with a graphical user interface which supports the construction and execution of data mining workflows, including web services used as workflow components. As a web application, the ClowdFlows platform poses no software requirements and can be used from any modern browser, including mobile devices. The constructed workflows can be declared either as private or public, which enables sharing the developed solutions, data and results on the web and in scientific publications. The server-side software of ClowdFlows can be multiplied and distributed to any number of computing nodes. From a developer’s perspective the platform is easy to extend and supports distributed development with packages. The paper focuses on big data processing in the batch and real-time processing mode. Big data analytics is provided through several algorithms, including novel ensemble techniques, implemented using the map-reduce paradigm and a special stream mining module for continuous parallel workflow execution. The batch mode and real-time processing mode are demonstrated with practical use cases. Performance analysis shows the benefit of using all available data for learning in distributed mode compared to using only subsets of data in non-distributed mode. The ability of ClowdFlows to handle big data sets and its nearly perfect linear speedup is demonstrated. 相似文献
992.
Selecting the most appropriate heuristic for solving a specific problem is not easy, for many reasons. This article focuses on one of these reasons: traditionally, the solution search process has operated in a given manner regardless of the specific problem being solved, and the process has been the same regardless of the size, complexity and domain of the problem. To cope with this situation, search processes should mould the search into areas of the search space that are meaningful for the problem. This article builds on previous work in the development of a multi-agent paradigm using techniques derived from knowledge discovery (data-mining techniques) on databases of so-far visited solutions. The aim is to improve the search mechanisms, increase computational efficiency and use rules to enrich the formulation of optimization problems, while reducing the search space and catering to realistic problems. 相似文献
993.
本文阐述了工作面采长与采空区防灭火的关系,并以石港公司为例,通过计算明确了工作面采长的取值范围,并结合经济效益进行综合分析,最终确定石港公司工作面设计采长应为120m。充分论证了合理设计工作面采长可以有效防治自燃。 相似文献
994.
The authors of this article have conducted a comparison study to investigate the construction characteristics of both single-well and two-well systems; two model experiments were conducted using large-size moulded rock salt specimens. An experimental platform was designed to simulate the process of leaching and a theoretical equation of calculating and predicting the cavern volume was derived. The experimental results illustrate that the variation trend of brine instantaneous concentration for single-well and two-well systems is identical, and an equilibrium state appears at last. Moreover, the equilibrium is reached early, after 5–8 pumping cycles. The construction rate in the two-well system is faster than the single-well system, and this phenomenon is observed mainly in the early periods (1–3 pumping cycles). Besides, the cavern shapes for the two construction methods are also found to be distinctive. The cavern of the single-well system has a circular cross section and an axisymmetric profile while that of the two-well system has an ovular cross section and a non-axisymmetric profile. 相似文献
995.
根据天湖山矿区极不稳定煤层的赋存条件,分析历史沿用的开拓开采方式采区通风存在的问题,立足现场实际,提出一些优化方案,并在实践中加以改进。 相似文献
996.
详细分析了我国矿山企业资本性人才的现状,指出了造成人才流失的原因及影响。提出国有矿山企业目前人才战略的重点,并结合我国国有矿山企业的实际情况,探索出创新人才管理机制的一系列对策。 相似文献
997.
Francesca Arcelli Fontana 《Information Sciences》2011,181(7):1306-1324
It is well known that software maintenance and evolution are expensive activities, both in terms of invested time and money. Reverse engineering activities support the obtainment of abstractions and views from a target system that should help the engineers to maintain, evolve and eventually re-engineer it. Two important tasks pursued by reverse engineering are design pattern detection and software architecture reconstruction, whose main objectives are the identification of the design patterns that have been used in the implementation of a system as well as the generation of views placed at different levels of abstractions, which let the practitioners focus on the overall architecture of the system without worrying about the programming details it has been implemented with.In this context we propose an Eclipse plug-in called MARPLE (Metrics and Architecture Reconstruction Plug-in for Eclipse), which supports both the detection of design patterns and software architecture reconstruction activities through the use of basic elements and metrics that are mechanically extracted from the source code. The development of this platform is mainly based on the exploitation of the Eclipse framework and plug-ins as well as of different Java libraries for data access and graph management and visualization. In this paper we focus our attention on the design pattern detection process. 相似文献
998.
999.
中德在焊接人员培训体系与焊接企业认证体系的多年合作为中国焊接体系与国际接轨、获取国际焊接学会授权奠定了基础;CANB,ATBs获得国际授权后,根据国内的实际情况,不断调整培养模式,促进国际焊接培训体系在国内的推广实施,20年来累计为国内培养了25000多名国际资质焊接专业人员(不含ISO 9606焊工等)。CANBCC获得国际授权10年来累计认证企业近600家,提升了焊接企业核心竞争力,促进了焊接企业高质量发展。 相似文献
1000.