全文获取类型
收费全文 | 2036篇 |
免费 | 251篇 |
国内免费 | 30篇 |
专业分类
电工技术 | 10篇 |
综合类 | 268篇 |
化学工业 | 249篇 |
金属工艺 | 60篇 |
机械仪表 | 120篇 |
建筑科学 | 766篇 |
矿业工程 | 6篇 |
能源动力 | 7篇 |
轻工业 | 25篇 |
水利工程 | 24篇 |
石油天然气 | 3篇 |
武器工业 | 8篇 |
无线电 | 25篇 |
一般工业技术 | 719篇 |
冶金工业 | 2篇 |
自动化技术 | 25篇 |
出版年
2024年 | 1篇 |
2023年 | 15篇 |
2022年 | 24篇 |
2021年 | 41篇 |
2020年 | 57篇 |
2019年 | 62篇 |
2018年 | 71篇 |
2017年 | 95篇 |
2016年 | 83篇 |
2015年 | 78篇 |
2014年 | 103篇 |
2013年 | 119篇 |
2012年 | 135篇 |
2011年 | 149篇 |
2010年 | 148篇 |
2009年 | 128篇 |
2008年 | 152篇 |
2007年 | 149篇 |
2006年 | 143篇 |
2005年 | 132篇 |
2004年 | 83篇 |
2003年 | 81篇 |
2002年 | 47篇 |
2001年 | 36篇 |
2000年 | 32篇 |
1999年 | 20篇 |
1998年 | 27篇 |
1997年 | 21篇 |
1996年 | 18篇 |
1995年 | 16篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有2317条查询结果,搜索用时 15 毫秒
1.
Thin-walled shell structures are characterized by a lightweight structural form with high strength. This structure has many applications in various engineering fields and is considered to be a basic tool in the modern industry. This study investigates the effect of CFRP on tanks after post-fire in order to examine the buckling and post-buckling of the cylindrical tanks. Herein, post-fire was introduced at different temperatures (150°C-600°C). Ten laboratory specimens in two groups with verified temperatures, under external pressure, are examined. The models were designed to demonstrate how repairing steel tanks, which are damaged by fire, by using carbon-fiber-reinforced polymer can recover lost capacity. The results of testing under different theories and codes were compared. This study shows that the initial buckling load of the temperature group increased by 30.82% to 57.09% compared to the temperature without-CFRP group. The overall buckling load of the temperature group increased by 37.01% to 67.74% compared to the temperature without-CFRP group. The collapse load of the temperature group increased by 27.04% to 52.64% compared to the temperature without-CFRP group. And using carbon-fiber-reinforced polymer on models, which are damaged by fire, can be an improvement behavior for the buckling and post-buckling specimen tests. 相似文献
2.
In this paper the fatigue properties of through-the-thickness reinforced joints are studied in detail. Unreinforced specimens, specimens reinforced with cold metal transfer welded titanium and steel pins and specimens reinforced with titanium z-pins are investigated. Besides classical S–N diagrams, hysteresis curves and stiffness based approaches are applied to improve the understanding of the mechanical behaviour of the joints in the progress of their fatigue life. Furthermore full field strain analysis gives information about damage initiation and growth in the joint section. 相似文献
3.
The Externally Bonded Reinforcement (EBR) technique using Carbon Fiber-Reinforced Polymers (CFRP) has been commonly used to strengthen concrete structures in flexure. The use of prestressed CFRP material offers several advantages well-reported in the literature. Regardless of such as benefits, several studies on different topics are missing. The present work intends to contribute to the knowledge of two commercially available systems that differ on the type of anchorage: (i) the Mechanical Anchorage (MA), and (ii) the Gradient Anchorage (GA). For that purpose, an experimental program was carried out with twelve slabs monotonically tested under displacement control up to failure by using a four-point bending test configuration. The effect of type of anchorage system (MA and GA), prestrain level (0 and 0.4%), width (50 mm and 80 mm) and thickness (1.2 mm and 1.4 mm) of the CFRP laminate, and the surface preparation (grinded and sandblasted) on the flexural response were the main studied parameters. Better performance was observed for the slabs: (i) with prestressed laminates, (ii) for the MA system, and (iii) with sandblasted surface preparation. 相似文献
4.
T300 carbon fiber reinforced polymer (CFRP) and 5083P-O aluminum (5083P-O Al) alloy bolted joints have been used in high-speed trains due to the advantages of light weight and high strength. However, high potential difference between the CFRP and 5083P-O Al will induce galvanic corrosion and result in accelerating corrosion rate of 5083P-O Al, which is a potential risk for its engineering applications. In this work, combination with the electrochemical analysis, surface and cross-section corrosive morphologies analysis, the galvanic corrosion behavior between CFRP/5083P-O Al bolted joints with and without anodizing in 3.5 wt.% NaCl spray was investigated. Results indicated that severe corrosion occurred on unanodized 5083P-O Al in the coupled regions of the CFRP/5083P-O Al bolted joint due to galvanic corrosion. With the content of sulfuric acid increasing, the thickness of each Al2O3 layer and atomic oxygen content increases significantly. 5083P-O Al anodized by the 135 g/L H2SO4 + 8 g/L H3BO3 mixed solution had the favorable Al2O3 film, which increased the resistance of 5083P-O Al by roughly three orders of magnitude, effectively improving the corrosion resistance of 5083P-O Al. 相似文献
5.
碳纤维加固受损框架节点与未受损框架节点的比较与分析 总被引:2,自引:1,他引:2
通过碳纤维加固受损框架节点与未受损框架节点的试验研究 ,对两者在承载力、刚度、位移等方面进行了比较和分析 相似文献
6.
碳纤维复合材料加固技术在工程中的应用 总被引:1,自引:2,他引:1
结合某钢筋混凝土构架加固工程实例,介绍了碳纤维加固技术的设计及施工工艺要点,通过对其在构架加固中的应用分析,提出了该加固技术的良好加固效果及强大竞争力。 相似文献
7.
外包环形碳纤维布加固钢筋混凝土梁的受剪承载能力试验研究 总被引:2,自引:0,他引:2
本文在试验的基础上 ,总结了外包环形碳纤维布加固钢筋混凝土梁受剪破坏的特征 ,分析了碳纤维布对加固梁受剪承载力的作用 ,讨论了加固梁的破坏机理和受力模型。提出了在剪跨内碳纤维布有效应变沿梁纵向的分布规律 ,并以此为基础 ,给出了适合工程设计之用的外包环形碳纤维布加固梁受剪承载力计算公式。经过与试验数据对比 ,发现二者吻合较好。 相似文献
8.
9.
碳纤维布与钢板黏结剪切性能研究 总被引:2,自引:0,他引:2
碳纤维布与钢板复合加固混凝土结构是一种新的加固形式,在其运用到实际加固工程时,关键是要保证碳纤维布与钢板之间的有效黏结。通过11组碳纤维布与钢板黏结剪切试验,分析了碳纤维布与钢板发生黏结剪切破坏的过程、破坏机理,并对碳纤维布的黏结宽度、碳纤维布的层数和黏结长度等对黏结剪切性能的影响进行了研究。研究结果表明,碳纤维布与钢板的有效黏结长度随着碳纤维布层数增加而增大,而与碳纤维布的宽度及粘贴长度无关;碳纤维布与钢板的极限黏结力随碳纤维布宽度增加而线性增大,且当黏结长度超过有效黏结长度后,极限黏结力不再随黏结长度增大而增加,但黏结破坏的延性得到改善。在试验研究的基础上提出了极限黏结力和有效黏结长度的计算公式,其计算结果和试验结果吻合较好,可为复合加固在工程上的应用提供参考。 相似文献
10.