全文获取类型
收费全文 | 31908篇 |
免费 | 3818篇 |
国内免费 | 1631篇 |
专业分类
电工技术 | 3219篇 |
技术理论 | 6篇 |
综合类 | 2891篇 |
化学工业 | 2671篇 |
金属工艺 | 1825篇 |
机械仪表 | 1786篇 |
建筑科学 | 4467篇 |
矿业工程 | 1015篇 |
能源动力 | 919篇 |
轻工业 | 2147篇 |
水利工程 | 1585篇 |
石油天然气 | 1210篇 |
武器工业 | 257篇 |
无线电 | 2153篇 |
一般工业技术 | 2870篇 |
冶金工业 | 1742篇 |
原子能技术 | 333篇 |
自动化技术 | 6261篇 |
出版年
2024年 | 185篇 |
2023年 | 442篇 |
2022年 | 888篇 |
2021年 | 1130篇 |
2020年 | 1278篇 |
2019年 | 1114篇 |
2018年 | 1107篇 |
2017年 | 1213篇 |
2016年 | 1456篇 |
2015年 | 1419篇 |
2014年 | 2289篇 |
2013年 | 2246篇 |
2012年 | 2395篇 |
2011年 | 2317篇 |
2010年 | 1799篇 |
2009年 | 1851篇 |
2008年 | 1726篇 |
2007年 | 2021篇 |
2006年 | 1882篇 |
2005年 | 1505篇 |
2004年 | 1270篇 |
2003年 | 1173篇 |
2002年 | 1036篇 |
2001年 | 912篇 |
2000年 | 691篇 |
1999年 | 544篇 |
1998年 | 348篇 |
1997年 | 244篇 |
1996年 | 206篇 |
1995年 | 131篇 |
1994年 | 110篇 |
1993年 | 69篇 |
1992年 | 74篇 |
1991年 | 40篇 |
1990年 | 43篇 |
1989年 | 40篇 |
1988年 | 35篇 |
1987年 | 15篇 |
1986年 | 13篇 |
1985年 | 14篇 |
1984年 | 18篇 |
1983年 | 13篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1975年 | 5篇 |
1964年 | 3篇 |
1963年 | 3篇 |
1961年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Software plays an increasingly important role in modern safety-critical systems. Although, research has been done to integrate software into the classical probabilistic risk assessment (PRA) framework, current PRA practice overwhelmingly neglects the contribution of software to system risk. Dynamic probabilistic risk assessment (DPRA) is considered to be the next generation of PRA techniques. DPRA is a set of methods and techniques in which simulation models that represent the behavior of the elements of a system are exercised in order to identify risks and vulnerabilities of the system. The fact remains, however, that modeling software for use in the DPRA framework is also quite complex and very little has been done to address the question directly and comprehensively. This paper develops a methodology to integrate software contributions in the DPRA environment. The framework includes a software representation, and an approach to incorporate the software representation into the DPRA environment SimPRA. The software representation is based on multi-level objects and the paper also proposes a framework to simulate the multi-level objects in the simulation-based DPRA environment. This is a new methodology to address the state explosion problem in the DPRA environment. This study is the first systematic effort to integrate software risk contributions into DPRA environments. 相似文献
12.
13.
Rudolf Habison 《International Journal of Project Management》1985,3(3):178-181
Meeting time and cost objectives in complex projects involves specific problems and risks. An attempt is made to analyse the components of total cost increase of a project caused by time delay. An outline is given as to how these considerations can be used to estimate cost increases in investors' decision situations as well as to ascertain fair contractual penalties and claims for compensation and for the evaluation of justified project acceleration costs. 相似文献
14.
Lussier Isabelle; Derevensky Jeffrey L.; Gupta Rina; Bergevin Tanya; Ellenbogen Stephen 《Canadian Metallurgical Quarterly》2007,21(2):165
The study of resilient children has overturned many deficit-focused models concerning the ontogenesis of children raised in adversity. This study explored the relationship between risk and protective factors, resilience, and youth gambling behavior. More specifically, this study examined the relative contribution of various risk and protective domains in relation to problem gambling behavior and examined whether youth identified as resilient (high risk exposure- high internalized protection) were as likely as those identified as vulnerable (high risk exposure-low internalized protection) to engage in excessive gambling behavior. The sample consisted of 1,273 students ages 12 to 19. The findings demonstrated that risk and protective factors each provide a unique contribution to the prediction model of gambling problems. Resilient and vulnerable youth differed significantly in their self-reported gambling severity. As well, resilient youth were not statistically distinguishable from low-risk exposure groups in terms of their gambling severity. Findings are interpreted with respect to resilience and prevention research. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
15.
16.
17.
用于高压电容器的SrTiO3基陶瓷 总被引:3,自引:0,他引:3
报道SrTiO3基陶瓷的制备方法和介电性质,给出了用此种陶瓷制成的高压电容器的试验结果,并对它位进行了讨论。 相似文献
18.
立式平管板U形管束的压水堆核电站蒸汽发生器安装至瞬变工况期间,管板上表面的铁基金属残余物的堆积和外来物的存在,以及商业运行后管板、传热管、管子支撑板等的低流速区域里沉积物的堆积要求进行蒸汽发生器的清洁度检查。介绍了蒸汽发生器二次侧清洁度的视频检查技术。该技术适用于蒸汽发生器安装至瞬变工况和投入商业运行后可能发生污染的各阶段的清洁度检查。 相似文献
19.
20.
Enhanced Image Detection on an ARM based Embedded System 总被引:2,自引:0,他引:2
This paper presents a new technique for thedetection of Integrated Circuits within images of Printed Circuit Boards autonomouslyand without the need to be assisted by CAD data. The technique is a key partof a suite of algorithms targeted for an embedded System On Chip architecturebased on the ARM7 platform for real time detection of PCB images for diagnosticpurposes. The technique has a significant reduction in complexity when comparedto conventional approaches such as the Hough Transform. The reduction in complexitymakes the approach ideal for an embedded vision application suchas the one described in this paper. This paper presents the technique, thetarget embedded architecture and results showing the reduction in complexitywhen compared to a Hough Transform. 相似文献