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   4422篇
  免费   218篇
  国内免费   88篇
电工技术   36篇
技术理论   2篇
综合类   913篇
化学工业   67篇
金属工艺   24篇
机械仪表   23篇
建筑科学   1892篇
矿业工程   56篇
能源动力   10篇
轻工业   74篇
水利工程   42篇
石油天然气   3篇
武器工业   2篇
无线电   272篇
一般工业技术   229篇
冶金工业   33篇
原子能技术   1篇
自动化技术   1049篇
  2024年   14篇
  2023年   85篇
  2022年   103篇
  2021年   103篇
  2020年   145篇
  2019年   95篇
  2018年   74篇
  2017年   74篇
  2016年   122篇
  2015年   126篇
  2014年   442篇
  2013年   292篇
  2012年   369篇
  2011年   396篇
  2010年   307篇
  2009年   393篇
  2008年   324篇
  2007年   307篇
  2006年   269篇
  2005年   175篇
  2004年   144篇
  2003年   109篇
  2002年   85篇
  2001年   55篇
  2000年   43篇
  1999年   31篇
  1998年   10篇
  1997年   8篇
  1996年   8篇
  1995年   4篇
  1994年   2篇
  1993年   1篇
  1991年   2篇
  1990年   2篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1980年   1篇
  1969年   1篇
  1966年   1篇
  1957年   1篇
排序方式: 共有4728条查询结果,搜索用时 15 毫秒
1.
The importance of cultural heritage for supporting the knowledge economy has promoted its digitisation and online publication. Many cultural heritage repositories have published millions of digitised items using semantic web technologies and Linked Data approaches. These repositories frequently use knowledge organisation systems to classify the resources, but the domain heterogeneity makes it difficult to know if they are the most suitable ones. This paper describes the process used to discover and profile the knowledge organisation systems used in the cultural heritage domain. Additionally, for those knowledge organisation systems with a thesaurus-like structure, a detailed quality analysis is performed. The results of this analysis can be used as a key factor for the selection of knowledge organisation systems in classification tasks.  相似文献   
2.
Abstract

In this article I argue that the study of cultural heritage preservation practices in the context of Muslim societies has been constructed—and obstructed—through specific historical trajectories and challenges. These originate within the field of cultural heritage preservation, through its own history and principles which have complicated the interplay between heritage and religious values and uses. As a result, situated studies of preservation practices in and by Muslim communities are in their infancy. In this article I revisit the points of contact between the emergence of a Eurocentric preservation dogma and its encounter with different articulations and practices related to Islam that are now approached as part of heritage assemblages and debates. I consider specific biases inherent in these discourses and propose, as a result, to approach the study of Islam and heritage in its own terms—rather than as an alternative to Western preservation paradigms.  相似文献   
3.
基于我国饮食类非物质文化遗产在政策层面、实施层面、科研层面的现状,文章从传承体系、保护体系、人文思想体系、普及体系和传播渠道的五个维度提出了我国饮食类非遗保护传承的路径。  相似文献   
4.
The Yaozhou kiln complex is a representative production center of ancient northern China, famous for the celadon production. In this work, bubbles, glassy matrix and residual crystals of celadon glazes produced from the Tang to Yuan Dynasty were analyzed by using optical microscopy, Raman spectroscopy and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). The results revealed that the Song, Jin and Yuan productions present bigger bubble and higher area ratios of the Si-O bending over stretching modes than the Tang and Wudai productions. This is consistent with firings at higher temperatures during Song, Jin and Yuan Dynasties. It is also in agreement with the historical studies, which revealed the change from wood-firing to coal-firing during Song Dynasty. The observation of calcium phosphate in Yaozhou productions indicated that the glaze ash had been used. No iron-based particle was identified by Raman spectroscopy in the glazes of all periods. The green color is certainly due to iron ion dispersed in the glassy matrix. Our study also confirmed no significant change in glaze raw materials used for Yaozhou productions from Tang to Yuan Dynasty.  相似文献   
5.
探析如何让京津冀地区独特的校园文化衍生品得到创新性发展,让文创产品更容易达到共情的目的,并传递不同的校园文化价值,围绕校园文化衍生品进行创新性设计。基于对京津冀地区不同校园文化背景的调研,在文旅融合背景下分析校园文化产品的现状与发展,以及有代表性的校园文化品牌。以清华大学文创产品为例,设计出具有创新性的校园文化产品,将文化元素与产品设计相结合。运用校园特色建筑、色彩、文化背景,发挥其原创性、传播性、文化性等优势,传播学校的理念及文化,扩大校园文化传播途径。在文旅融合背景下,设计出独特的校园文化衍生产品,传承文化内涵与理念,并提高校园文化认同感与归属感,成为京津冀地区发展校园文化的趋势,从而推动文化旅游产业的发展。  相似文献   
6.
Indoor Air Quality monitoring in cultural institutions is of particular concern to protect these places and the cultural heritage content. An indoor monitoring campaign was performed in three museums in Florence (Italy) to determine the occurrence and levels of volatile organic compounds (VOCs). VOCs of interest included BTEX (benzene, toluene, ethylbenzene, xylenes), terpenes, aldehydes, organic acids, and cyclic volatile methyl siloxanes (cVMS). The most abundant VOCs in all samples analyzed were BTEX, which were strictly related to the traffic source, followed by siloxanes and terpenes. Among BTEX, toluene was always the most abundant followed by xylenes, ethylbenzene, and benzene. cVMS in exhibition rooms with the presence of visitors showed higher values compared to samples collected when the museums were closed. Terpenes showed not only the influence of vegetation-biogenic sources surrounding a museum but could also be related to the wood used for the construction of showcases and furniture and the use of cleaning products. Data obtained also showed the presence of organic acids and aldehydes whose source can be traced back to exhibits themselves and wood-based furniture. Assessing the levels of organic acids in museums is important because, over time, it can cause deterioration of the artifacts.  相似文献   
7.
In earlier articles, we determined the spatial distributions and concentrations of all pigments used by Van Gogh in his painting Field with Irises near Arles. The colors of some pigments are expected to have changed over time, especially those of chrome yellow, cochineal, and eosin lake. For all pigments in this painting, we made physical paint reconstructions by following historical sources on raw materials and production processes, and we determined their optical properties. We combined this with pigment concentration maps to reconstruct the original colors of the painting digitally. When substituting the reconstruction paints into the calculations, we found that technical‐scientific data was not sufficient to resolve several issues. In those cases, discussions within the broad interdisciplinary team allowed us to make informed decisions. These issues refer to the representation of the sky area, and the original contributions of the red lake pigments to local colors. The digitally reconstructed colors of the painting show that due to discoloring of red lake pigments, the irises in the field have changed from a warm purple to purplish blue, and many pink spots in the field have turned to white. The range of yellows in the field has decreased and partly turned to dark brown. The digital reconstruction gives a better understanding of the color scheme used by Van Gogh when compared to remarks the artist made in letters when describing this painting. Also, the original color composition is seen to be aligned with color theories on which Van Gogh based his work.  相似文献   
8.
This review presents the results of a conference on ikat textiles organized in the context of the exhibition Striking Patterns: Global Traces in Local Ikat Fashion at the Museum der Kulturen Basel, Switzerland (October 2016 to March 2017). Academics and professional experts, some of them working for NGOs, debated often neglected potentialities as well as the future of contemporary ikat design and other intricately patterned handwoven textiles: the significance of new patterns; intellectual property rights; and educational encouragement. The general focus lay on the controversially perceived innovation of textile patterns in Indonesia and Timor-Leste. We will here present the main arguments of the discussion and our own suggestions for further research.  相似文献   
9.
MgAl2O4-MgO eutectic ceramics were fabricated by the laser-heated floating zone (LFZ) method with various growth rates to assess its possible beneficial effect on microstructural aspects and mechanical properties. It was determined that the growth rate optimizing the microstructure and mechanical properties is 750 mm/h; below this value, coarsening of the fibrous microstructure takes place with a degradation of these properties. In the extreme case of 50 mm/h growth rate, the presence of undesirable transverse cracks was unavoidable. Thanks to the high growth rate of 750 mm/h, ultra-fine fibrous microstructure MgAl2O4-MgO eutectic ceramics can thus be fabricated with greater hardness (15.5 GPa from Vickers indentation and 22 GPa from nanoindentation) and flexural strength (?345 MPa). It is reported that hardness scales with the interfiber spacing λ according to a law of the type lnλ/λ, contrary to the assumed Hall-Petch-like dependence. This proposed law can be explained in terms of dislocation hardening induced by the MgO fibers.  相似文献   
10.
采用A20-MBR系统处理校园污水,考察该工艺对各类污染物的去除效果及其关键影响因素。研究结果表明:A。O—MBR工艺在稳定运行条件下各项出水水质优良,但由于受碳源限制,出水TP浓度不能稳定达标。水温对A20-MBR系统去除COD。和NH3一N的效果影响较小,而对TN去除效果的影响较为显著;低水温条件下维持系统污泥质量浓度在6g/L以上可获得较高的NH3-N及TN去除率;为保障处理效果和降低运行成本,低水温条件下(9~12oc),应提高DO的质量浓度至1.0mg/L左右。  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