全文获取类型
收费全文 | 23590篇 |
免费 | 2525篇 |
国内免费 | 799篇 |
专业分类
电工技术 | 1506篇 |
技术理论 | 19篇 |
综合类 | 2490篇 |
化学工业 | 1190篇 |
金属工艺 | 1277篇 |
机械仪表 | 1939篇 |
建筑科学 | 3006篇 |
矿业工程 | 474篇 |
能源动力 | 746篇 |
轻工业 | 1871篇 |
水利工程 | 435篇 |
石油天然气 | 496篇 |
武器工业 | 252篇 |
无线电 | 1005篇 |
一般工业技术 | 2614篇 |
冶金工业 | 4265篇 |
原子能技术 | 115篇 |
自动化技术 | 3214篇 |
出版年
2025年 | 40篇 |
2024年 | 566篇 |
2023年 | 506篇 |
2022年 | 625篇 |
2021年 | 780篇 |
2020年 | 898篇 |
2019年 | 760篇 |
2018年 | 753篇 |
2017年 | 841篇 |
2016年 | 943篇 |
2015年 | 978篇 |
2014年 | 1426篇 |
2013年 | 1494篇 |
2012年 | 1311篇 |
2011年 | 1639篇 |
2010年 | 1303篇 |
2009年 | 1330篇 |
2008年 | 1203篇 |
2007年 | 1282篇 |
2006年 | 1245篇 |
2005年 | 1105篇 |
2004年 | 950篇 |
2003年 | 840篇 |
2002年 | 736篇 |
2001年 | 657篇 |
2000年 | 388篇 |
1999年 | 347篇 |
1998年 | 231篇 |
1997年 | 216篇 |
1996年 | 184篇 |
1995年 | 140篇 |
1994年 | 125篇 |
1993年 | 94篇 |
1992年 | 63篇 |
1991年 | 40篇 |
1990年 | 61篇 |
1989年 | 45篇 |
1988年 | 44篇 |
1987年 | 37篇 |
1986年 | 30篇 |
1984年 | 27篇 |
1966年 | 28篇 |
1965年 | 32篇 |
1964年 | 61篇 |
1963年 | 49篇 |
1961年 | 44篇 |
1959年 | 32篇 |
1957年 | 34篇 |
1955年 | 46篇 |
1954年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
《International Journal of Pressure Vessels and Piping》1996,66(1-3):187-198
The limit carrying capacity of gas pipelines having corrosion defects were evaluated by means of an improved FEM analysis, together with the ANSI/ASME defect judgement and an experimental verification. When compared with our past presentation at the proceedings of the CAPE'93 Colloquium (dealing with reproduced defects), this paper evaluates the remaining lifetime of a pipeline having natural faults. The new improved analysis includes geometrical nonlinearities leading to a modification of limit state parameters and thus matching better with actuality. This presented work was initiated by the firm of Trans-Gas in Prague after having had a pipeline inspected proving some parts of it as being heavily corroded. The task in hand was to determine the remaining pipeline lifetime with the view to at least a two-year period. 相似文献
4.
Service life planning comprises a model for the determination of a reasonable expected service life for buildings and components, and it establishes a routine for the assessment of design alternatives. A design option is considered reasonable when it meets or exceeds performance requirements over time that have been drawn up specifically for the specific project. Due to this assessment reference, there is a very evident link to the concept of performance-based building. Any stakeholder involved in the value chain or in the design process of the building, as well as regulators and building users, can express performance requirements. Identified requirements, both in relevance and in quality, will vary with the stakeholder and his/her perspective of interest. As building sector manufacturers develop most products with reference to standards rather than with reference to specific requirements, there is no direct link from user requirements to the product design. Instead, the building designer has the responsibility to ensure performance requirements are met by the performance of products integrated into the design. As these design decisions also have to be made at the material and component level, a performance-based building would benefit from an established rationale that enables the communication of performance requirements across the relevant system levels in the relevant design processes. A path for the connection of the established concepts of service life planning and performance-based building is presented. The aim is to identify key elements that need to be developed for the successful linkage of performance-based building with service life planning. 相似文献
5.
严诗琴 《数码设计:surface》2014,(11):120-122
"火桶"是南方传统的御寒器物,它具有造型简单,取材方便,功能实用多样的特点,凝聚了民间朴素造物的思想。同时,火桶所具有着深厚的人文特点和文化内涵。文章以黔东南镇远地区民间火桶为例,分析其形态、结构、功能及人机关系等内容,探究民间造物的设计巧思。 相似文献
6.
运用博弈论的基本思想,通过构造一个资源生产供应链,从资源保护这个角度出发,以资源生产供应链中的节点企业——资源开采商开采自然资源为例,对资源生产供应链履行社会责任的内在动力进行了研究。结果表明:对资源开采商合作开采带来的收益增量进行合理分配,既能使资源开采商进行合作,又能实现供应链系统与各资源开采商的帕累托最优。 相似文献
7.
Yuan-Chih Yu 《中国科学:信息科学(英文版)》2014,57(3):1-10
As the use of smartphones become popular,people heavily depend on smartphone applications to deal with their social activities.For this reason,traditional message texting between mobile applications does not fulfill the versatile requirements of social networking.Many mobile applications use multimodality to deliver multimedia messages including sticker,voice and photo message,video call,and snap movie to enhance the communicative capability.However,without face-to-face interaction,people may fail to detect the other side’s non-verbal social behavior such as fine-grain facial expressions,body movements,or hand gesture.During social interaction,non-verbal behavior conveys information about the involved individuals and help the speakers express their social emotion in an implicit way.It is so important for real-world face-to-face interaction but is often blocked on the mobile telephony.To cope with this problem,we propose an afective computing model to assist the representation of social emotion and then help the progress of social interaction on the mobile telephony.In this model,for the purpose of real-time afective analysis,we delegate the computing loading to the cloud side service and enhance the system’s scalability and availability.The result of this experiment approves the feasibility of our system design for the applications of social intelligent.Also,the system provides a research framework of the social intelligent system on the mobile telephony. 相似文献
8.
赵永兴 《计算机与数字工程》2015,(1):128-132
开关电源具有体积小、重量轻、效率高等诸多优点,凭借其自身的诸多优势,开关电源已经广泛应用于航空航天、通信、以及电子类。由于应用领域的广泛性,开关电源的可靠性引起了人们的重视。论文以阿伦尼斯(Arrhenius)模型为基础,设计了一整套针对开关电源的可靠性评价和寿命预计的试验方案。该方案对试验器件施加温度应力,加速器件的失效过程,并通过一定的加速模型和统计分析方法,外推出正常工作条件下产品的寿命特征。 相似文献
9.
奥康纳小说刻画了一群在社会转型中丧失财产和地位的南方老白人,他们的物质生活每况愈下,精神上经历着错位和失落,终日沉醉在过往的幸福时光之中,对当下世风大加批评。这种美化过去生活、消极反抗现实的处世态度使得他们的生存日益边缘化,甚至还会引发极为惨重的后果。对那些固守传统、恋旧讽今的长者,奥康纳在善意嘲讽的同时,也表达出真挚的理解和同情。 相似文献
10.
环保高性能防腐涂料驱动未来市场 总被引:5,自引:0,他引:5
介绍了防腐涂料的新品种和防腐体系的选择,指出了我国防腐涂料的发展趋势。 相似文献