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   1455篇
  免费   6篇
  国内免费   2篇
电工技术   6篇
综合类   3篇
化学工业   94篇
金属工艺   10篇
机械仪表   12篇
建筑科学   24篇
矿业工程   2篇
能源动力   8篇
轻工业   28篇
水利工程   2篇
石油天然气   2篇
无线电   43篇
一般工业技术   51篇
冶金工业   1046篇
原子能技术   12篇
自动化技术   120篇
  2022年   4篇
  2021年   5篇
  2020年   3篇
  2019年   4篇
  2018年   3篇
  2017年   3篇
  2016年   3篇
  2014年   5篇
  2013年   37篇
  2012年   7篇
  2011年   13篇
  2010年   10篇
  2009年   14篇
  2008年   26篇
  2007年   17篇
  2006年   13篇
  2005年   14篇
  2004年   18篇
  2003年   21篇
  2002年   12篇
  2001年   11篇
  2000年   15篇
  1999年   43篇
  1998年   329篇
  1997年   184篇
  1996年   124篇
  1995年   76篇
  1994年   66篇
  1993年   64篇
  1992年   20篇
  1991年   33篇
  1990年   15篇
  1989年   24篇
  1988年   21篇
  1987年   19篇
  1986年   9篇
  1985年   19篇
  1984年   4篇
  1983年   7篇
  1982年   7篇
  1981年   4篇
  1980年   9篇
  1978年   12篇
  1977年   27篇
  1976年   42篇
  1975年   9篇
  1973年   3篇
  1971年   3篇
  1944年   3篇
  1942年   2篇
排序方式: 共有1463条查询结果,搜索用时 15 毫秒
51.
The ring-section technique has been studied by the Standard Testing Procedure Committee of the Glass Container Association, and a tentative Standard Method of Examining and Grading Glass Container Ring Sections is proposed. The scope, method, and frequency of sampling, method of examination, and the methods used for ware-quality grading and glass-quality grading are described.  相似文献   
52.
To a base glass containing 14% of sodium oxide, 12% of dolomite lime, and 74% of silica, barium oxide and zinc oxide, respectively, were systematically substituted for (a) Na2O, (b) CaO.MgO, and (c) SiO2 in amounts of 1, 3, and 5%. The effects of these substitutions on such physical properties as liquidus temperature, viscosity, deformation temperature, density, fiber softening point, coefficient of expansion, and the resistance of the glasses to dilute acid and distilled water are presented.  相似文献   
53.
54.
55.
56.
57.
The term ‘hybrid concrete construction’ (HCC) is used to describe the combination of concrete construction methods, e.g. in‐situ concrete and precast concrete, with one another or with other materials, e.g. steel. Although it could be argued that most buildings employ such combinations, HCC is the deliberate integration of different construction techniques to achieve a cost, speed or other performance benefit. UK government has been concerned that the construction industry suffers from poor management and exchange of tacit knowledge which can disappear after project teams ‘break up’. The completion of several innovative and high profile HCC projects was considered to be a major opportunity to capture project teams' tacit knowledge in this area. The objective of the research was to compile a best practice process model, such that project teams could be better informed as to their roles and responsibilities and thus be better equipped to deliver a building to the client's satisfaction, by using HCC. Interviews and knowledge capture workshops were used to extract lessons that lay embedded in both individuals and teams. The main conclusions were that successful HCC projects were characterized for example, by the development of an ethos of trust, the early involvement of specialists (such as precasters) and the effective management of both tacit and explicit knowledge. The research builds on previous work in the area by identifying best practice information on design, specification and construction factors for HCC and, in addition, some transferable lessons on knowledge capture techniques.  相似文献   
58.
Hybrid concrete construction (HCC) uses a combination of in-situ and precast concrete and is an example of ‘mixed’ construction, which is the term for an innovative combination of different materials or framing methods. Examples of HCC exist in many countries to fulfil varying structural requirements, so it is not clear why HCC is not better used in the UK. Research was undertaken to gain a better understanding of the selection and use of HCC. Two case study projects were investigated to explore decision-making criteria, the roles of project participants and the challenges particular to HCC. The findings suggest that HCC is selected when measurable cost or programme advantages are not the most important criteria, but where other factors such as satisfying architectural requirements (finish, colour, etc.) or operational demands (such as internal comfort or maintenance) are critical. In both cases, clients and architects were found to be the most influential team members in the frame-selection process.

La construction en béton hybride (HCC) utilise une combinaison de béton in situ et de béton précoulé; c'est un exemple de ‘construction mixte’; cette expression définit une combinaison innovante de différents matériaux et méthodes de coffrage. Il existe des exemples de HCC dans de nombreux pays qui répondent à différentes exigences structurales; on peut donc difficilement expliquer pourquoi la HCC n'est pas mieux utilisée au Royaume-Uni. Des recherches ont été entreprises pour mieux comprendre les choix et les usages de la HCC. Deux études de cas ont été engagées, l'objectif étant d'explorer les critères décisionnels, le rôle des participants à ces projets et les défis particuliers propres à la HCC. Les résultats laissent à penser que la HCC est retenue lorsque le coût mesurable ou les avantages du programme ne sont pas les critères les plus importants et lorsque d'autres facteurs comme la réponse aux exigences architecturales (finition, couleur, etc.) ou d'autres exigences opérationnelles (comme le confort intérieur ou la maintenance) sont critiques. Dans les deux cas, les clients et les architectes sont apparus comme les membres les plus influents des équipes lors du processus de sélection du cadre.

Mots clés: processus de conception, construction en béton hybride, construction mixte, critères de performances, cadre structural  相似文献   
59.
The tear film is a multi-layer fluid that covers the corneal and conjunctival epithelia of the eye and provides lubrication, nutrients, and protection from the outside environment. Tear fluid contains a high concentration of proteins and has thus been recognized as a potential source of biomarkers for ocular disorders due to its proximity to disease sites on the ocular surface and the non-invasive nature of its collection. This is particularly true in the case of dry eye disease, which directly impacts the tear film and its components. Proteomic analysis of tear fluid is challenging mainly due to the wide dynamic range of proteins and the small sample volumes. However, recent advancements in mass spectrometry have revolutionized the field of proteomics enabling unprecedented depth, speed, and accuracy, even with small sample volumes. In this study using the Orbitrap Fusion Tribrid mass spectrometer, we compared four different mass spectrometry workflows for the proteomic analysis of tear fluid collected via Schirmer strips. We were able to establish a method of in-strip protein digestion that identified >3000 proteins in human tear samples from 11 healthy subjects. Our method offers a significant improvement in the number of proteins identified compared to previously reported methods without pooling samples.  相似文献   
60.
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