首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6459篇
  免费   332篇
  国内免费   348篇
电工技术   81篇
技术理论   8篇
综合类   830篇
化学工业   652篇
金属工艺   98篇
机械仪表   184篇
建筑科学   517篇
矿业工程   183篇
能源动力   126篇
轻工业   299篇
水利工程   102篇
石油天然气   65篇
武器工业   1025篇
无线电   626篇
一般工业技术   668篇
冶金工业   535篇
原子能技术   42篇
自动化技术   1098篇
  2024年   8篇
  2023年   58篇
  2022年   85篇
  2021年   123篇
  2020年   121篇
  2019年   98篇
  2018年   84篇
  2017年   330篇
  2016年   344篇
  2015年   336篇
  2014年   449篇
  2013年   353篇
  2012年   309篇
  2011年   514篇
  2010年   383篇
  2009年   442篇
  2008年   336篇
  2007年   421篇
  2006年   409篇
  2005年   307篇
  2004年   246篇
  2003年   251篇
  2002年   193篇
  2001年   171篇
  2000年   158篇
  1999年   124篇
  1998年   71篇
  1997年   59篇
  1996年   48篇
  1995年   33篇
  1994年   47篇
  1993年   23篇
  1992年   19篇
  1991年   14篇
  1990年   22篇
  1989年   21篇
  1988年   10篇
  1986年   12篇
  1985年   6篇
  1984年   7篇
  1982年   5篇
  1970年   5篇
  1967年   4篇
  1966年   6篇
  1965年   5篇
  1964年   9篇
  1963年   5篇
  1961年   5篇
  1960年   5篇
  1955年   6篇
排序方式: 共有7139条查询结果,搜索用时 62 毫秒
11.
12.
13.
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   
14.
The Office of Technology Assessment (OTA), which was created by the Technology Assignment Act of 1972, was—and still remains even after its abolishment in 1995—a unique congressional agency. OTA provided members of Congress with their own means of understanding and evaluating complex science and technology matters—of which there are no shortages. It spurred an entire literature of academic research both about OTA and the idea of technology assessment more generally. Understanding the legislative history and implementation of the Technology Assessment Act is crucial not just for scholarship, though. OTA was a blueprint for institutionalizing politically accountable technology assessment. Even as technologies advance at rapid rates, OTA still offers valuable lessons that scholars and policy-makers alike ought to glean. This paper places OTA in a contemporary context of (institutionalized) technology assessment. It contributes to a better understanding of OTA's origins by tracing its lineage to a set of federal reports beginning in 1929. It then analyzes OTA's response to pragmatic implementation questions of how to strike a balance between speed, depth, scope, and temporal focus. Lastly, it uses a public values framework to critique OTA's failure to adequately incorporate participatory elements into its processes.  相似文献   
15.
16.
17.
A simple synthetic method without organic template is proposed for the synthesis of Ni-silicate. The resulting Ni-phyllosilicates are reconstructed by hydrothermal treatment to a porous structure with a high surface area (552 m2 g−1). Notably, the residual filtrate has a Ni2+ ion content of less than 0.1 ppm, and therefore satisfies the effluent standard in Taiwan (<1.0 ppm). As a result, it can be disposed of directly without the need for additional treatment. The effects of the pH value and hydrothermal treatment time on the structure, morphology, and surface area of the Ni-silicate composites have been investigated. When applied to hydrogen production, the mesoporous Ni-silicate shows a high catalytic capability (>99%) toward ammonia decomposition at a temperature of 400°C. Overall, the proposed synthetic method is facile and easily extendable to the production of other metal-silicate materials for hydrogen generation.  相似文献   
18.
Brian Dixon 《CoDesign》2020,16(2):97-110
ABSTRACT

Participatory design’s (PD) shift from the workplace to civic settings has led to a reorientation of the field’s political bearings. Informed by science and technology studies, practice is now often framed in terms of design things, infrastructuring, and John Dewey’s concept of ‘publics’. Taking the publics concept as a starting point, the present article seeks to contribute by providing a broader outline of Dewey’s democratic vision. It is proposed that Dewey’s vision may be seen to offer a potentially useful perspective that directly relates the ‘publics’ concept to the areas of freedom, experientialism, and the institutions of government. Linking to contemporary developments in PD and beyond, the vision is seen to carry conceptual and practical implications, which, if borne out, would connect the discipline’s capacity to ‘spark’ publics into being to the processes of policy formation and institutional reform.  相似文献   
19.
This study aims to test two hypotheses: teaching building information modeling (BIM) in relation to construction science provides students with a remarkable understanding of the nature of construction science (Hypothesis 1), and if the student has positive attitude toward the use of the BIM program, then efficiency by which construction science is taught by its means is improved (Hypothesis 2). Results and process of a case study with a novel teaching methodology were discussed in terms of the benefits of the students. A questionnaire study was conducted on the student group with which the case study was performed to test each student's attitude. Results were evaluated statistically. When BIM is integrated with the teaching of basic construction courses within architecture degree programs, the students understood the building system principles simply and effectively. As a result of the statistical analysis, the students find the applied method effective. Moreover, their attitude toward BIM affects the process.  相似文献   
20.
水文水资源学家陈守煜先生学术研究的知识图谱分析   总被引:3,自引:0,他引:3  
为探索水文水资源学家陈守煜先生学术研究历程及其演变规律,以其335篇文献作为数据基础,采用共现分析等文献计量可视化分析方法,通过文献发表的时间分布、学科和期刊分布、高被引文献分布和研究主题等方面的知识图谱分析,系统分析了陈先生的学术研究历程。结果显示:陈守煜先生学术研究生命周期历时达62年,在其60岁后出现了2个学术创新高峰期;其学术研究特色荟萃于其河渠非恒定流计算、模糊集理论的水文水资源应用、模糊水文水资源学基本理论、模糊聚类-识别-优选统一理论、可变模糊集理论和可变模糊集理论的水文水资源应用6个研究主题,其中主题1为后续的5个模糊水文水资源学创新主题奠定了数值计算的研究方法论,主题2为模糊集现有理论的应用探索,主题3至主题5为面向工程应用的模糊集理论不断深入创新,主题6为可变模糊集理论的应用探索,形成了"紧密结合应用-持续理论创新-创新理论再应用"这种理论与实践互馈的研究特色。他每一阶段的研究目标比较集中、明确,与其研究主题密切对应,显著提高了研究效率;他的学术研究影响广泛,合计被引8554次,缘于他的源头理论创新。陈先生的研究,理论与应用不断互馈,贵在厚积薄发、深入钻研、持续创新,其研究理念和方法论,对水利科学的学术创新研究具有重要的启示作用和深远影响。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号