全文获取类型
收费全文 | 4287篇 |
免费 | 276篇 |
国内免费 | 172篇 |
专业分类
电工技术 | 58篇 |
技术理论 | 6篇 |
综合类 | 493篇 |
化学工业 | 239篇 |
金属工艺 | 68篇 |
机械仪表 | 79篇 |
建筑科学 | 1436篇 |
矿业工程 | 74篇 |
能源动力 | 57篇 |
轻工业 | 243篇 |
水利工程 | 130篇 |
石油天然气 | 528篇 |
武器工业 | 13篇 |
无线电 | 85篇 |
一般工业技术 | 305篇 |
冶金工业 | 570篇 |
原子能技术 | 48篇 |
自动化技术 | 303篇 |
出版年
2024年 | 8篇 |
2023年 | 35篇 |
2022年 | 72篇 |
2021年 | 96篇 |
2020年 | 125篇 |
2019年 | 81篇 |
2018年 | 82篇 |
2017年 | 121篇 |
2016年 | 119篇 |
2015年 | 130篇 |
2014年 | 247篇 |
2013年 | 281篇 |
2012年 | 253篇 |
2011年 | 306篇 |
2010年 | 243篇 |
2009年 | 286篇 |
2008年 | 240篇 |
2007年 | 245篇 |
2006年 | 247篇 |
2005年 | 218篇 |
2004年 | 175篇 |
2003年 | 170篇 |
2002年 | 165篇 |
2001年 | 127篇 |
2000年 | 98篇 |
1999年 | 78篇 |
1998年 | 50篇 |
1997年 | 41篇 |
1996年 | 39篇 |
1995年 | 33篇 |
1994年 | 38篇 |
1993年 | 18篇 |
1992年 | 31篇 |
1991年 | 15篇 |
1990年 | 19篇 |
1989年 | 16篇 |
1988年 | 14篇 |
1987年 | 18篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1981年 | 5篇 |
1974年 | 7篇 |
1968年 | 6篇 |
1961年 | 5篇 |
1959年 | 10篇 |
1957年 | 7篇 |
1955年 | 4篇 |
1954年 | 14篇 |
排序方式: 共有4735条查询结果,搜索用时 31 毫秒
1.
《Geotextiles and Geomembranes》2020,48(6):802-811
Construction of this 67 m high RSS was completed in December 2006. After seven years in-service, a tension crack was observed at the top of the slope. In March 2015 this RSS structure catastrophically collapsed. This RSS structure collapsed in a compound failure mode; as the failure plane passed beneath, partially behind, and partially through the reinforced soil mass. The failure plane beneath the RSS was along a shale-claystone interface. The failure surface partially behind the RSS was along sandstone bedrock with water-seeping bedding planes dipping out of the rock mass. The failure surface through the upper portion of the RSS is where the geogrid reinforcement was overwhelmed by stresses originating from underlying deformation. The RSS collapse occurred after 8.3 years in-service as the shear strength along the shale-claystone interface decreased and approached the fully softened strength. The primary causative factors of this failure are: (i) an insufficient subsurface investigation program and interpretation of data for design and detailing; (ii) insufficient specifications and construction plan details for both foundation preparation and rock backcut benching; (iii) insufficient foundation preparation and rock backcut benching during construction; and (iv) adaptations to the design made during construction. 相似文献
2.
Lukáš Kolek Vít Šisler Patrícia Martinková Cyril Brom 《Journal of Computer Assisted Learning》2021,37(5):1348-1369
This study investigates a video game's effects on implicit and explicit attitudes towards depicted historical events in the short- and long-term on a sample of 148 young adults. We used, as an intervention tool, a serious game Czechoslovakia 38–89: Borderlands that deals with the expulsion of the Sudeten Germans from the former Czechoslovakia after the WWII. Results showed more negative pretest-posttest explicit attitude changes towards the expulsion on a general level (d = −0.34) and a specific level (d = −0.53) compared to the control group. Over the long-term, group differences in attitude change remained significant for the specific level (d = −0.44), but not for general one (d = −0.16). Exploratory analysis on the item level indicated that especially attitudes towards the expulsion's (un)fairness were affected by the game. However, no significant changes were found in implicit attitudes in the experimental group. This study is the first of such scale to empirically investigate video games' effects on a society's historical awareness. 相似文献
3.
进行了圆柱振动台试验,对模型的加速度反应数据进行获取。试验表明,随着地震的加速度峰值的不断增加,圆柱顶部加速度极值不断增加。柱顶的加速度响应有着增大的趋势,且极值比输入的加速度的极值有一定的放大。 相似文献
4.
5.
汉代是中国园林的形成阶段,不仅园林建筑物有所增加,成为住宅的延伸与扩展,而且人工造景比重也增大,造园要素趋于完备。园林的内容与功能随着社会生活的改变而逐步多样和完善,不仅是射猎、走狗、跑马的场所,还可以是游船、宴乐、赏鱼虫走兽、观看百戏的地方。造园在布局上也采用灵活多变的手法,按功能的需要,穿插安置不同形式的厅堂、楼阁、亭榭等。通过对鲁灵光殿时代背景及汉代园林、建筑营造形式的深入研究,结合文献的相关记述,梳理出鲁灵光殿的沿革,并以此为依据,对鲁灵光殿进行复原。 相似文献
6.
传统文化电视节目在探索发展的过程中,选题逐渐聚焦中国风物人文,视野逐步向百姓生活延伸,立意兼顾文化内涵与百姓情感需求,编排制作节目内容与造型双发展。在此基础上,传统文化节目迎来更大的繁荣。 相似文献
7.
Angela Ki Che Leung 《Centaurus; international magazine of the history of science and medicine》2020,62(2):257-262
This paper looks at the role of state and society in the history of epidemic governance in China for an appreciation of the way China manages the current COVID-19 epidemic. 相似文献
8.
Sason Shaik Miri Karni David Danovich Yitzhak Apeloig 《Israel journal of chemistry》2015,55(11-12):1167-1176
We tell the story of the Lise Meitner-Minerva Center, its establishment and activities, its members and their scientific activity, and its instrumental role in weaving intense relationships with the theoretical community in Germany, and in amalgamating the Israeli community of computational quantum chemistry into a national center that enjoys a high international reputation. 相似文献
9.
Huanjun Jiang Haifeng Bu Liusheng He 《The Structural Design of Tall and Special Buildings》2020,29(14)
A new type of self‐centering beam‐column joint with installed steel arc plates is proposed in this study. First, mechanical behavior of the self‐centering joint using prestressed steel strands to provide the centering force is theoretically analyzed in detail, followed by experimental validation. New joints with different arc plate parameters are designed and tested under cyclic loading. Test results show that the hysteretic curve of the new joint exhibits typical characteristic of self‐centering capacity. By parametric analysis of five design parameters of the arc plate, it is found that vector height has the greatest influence on the joint's moment‐rotation skeleton curve, which is consistent with experimental findings. A simplified model of the joint is built in OpenSees to simulate its hysteretic behavior, which agrees well with the tested results. To demonstrate the effectiveness of the new joint to improve the seismic performance of the overall structure, a series of nonlinear time history analysis on a steel frame structure with the new joint under earthquakes are conducted, which show that the joint is particularly effective in reducing the residual interstory drift response. 相似文献
10.
历史的书写,从来都逃避不了时代的主观性;而所谓历史的真实,亦无法摆脱客体的相对性,因而呈现出错综交杂的表象,难以一窥全貌。本文重拾中国营造学社开启的,以实物和史料相互印证的研究方法;基于多个真实的遗产保护案例,通过建筑本体勘查、历史影像的三维数字化还原、特殊节点构造的拆解分析、实物湮灭后的类型化推测等工作,试图破解特殊的建筑结构体系及做法,揭示建筑物背后隐藏的历史和文化。一切历史都是当代史,遗产保护实践中的探索与反思,不仅可以更好地叙述一段贴近真实的历史,同时,也构筑起一个深具历
史感的当下。 相似文献