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   320篇
  免费   7篇
电工技术   12篇
综合类   1篇
化学工业   37篇
金属工艺   1篇
机械仪表   7篇
建筑科学   16篇
能源动力   3篇
轻工业   47篇
水利工程   3篇
石油天然气   1篇
无线电   20篇
一般工业技术   28篇
冶金工业   63篇
原子能技术   4篇
自动化技术   84篇
  2022年   1篇
  2021年   2篇
  2020年   3篇
  2019年   3篇
  2018年   3篇
  2017年   1篇
  2016年   9篇
  2015年   4篇
  2014年   9篇
  2013年   29篇
  2012年   4篇
  2011年   10篇
  2010年   5篇
  2009年   19篇
  2008年   10篇
  2007年   18篇
  2006年   16篇
  2005年   13篇
  2004年   14篇
  2003年   7篇
  2002年   15篇
  2001年   6篇
  2000年   15篇
  1999年   11篇
  1998年   13篇
  1997年   12篇
  1996年   8篇
  1995年   5篇
  1994年   5篇
  1993年   7篇
  1992年   2篇
  1991年   3篇
  1990年   8篇
  1989年   1篇
  1988年   3篇
  1985年   5篇
  1984年   3篇
  1983年   4篇
  1982年   2篇
  1981年   3篇
  1980年   2篇
  1979年   2篇
  1978年   2篇
  1977年   1篇
  1976年   4篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
  1959年   1篇
排序方式: 共有327条查询结果,搜索用时 15 毫秒
1.
2.
3.
Chronic Kidney Disease (CKD) is associated with sustained inflammation and progressive fibrosis, changes that have been linked to altered connexin hemichannel-mediated release of adenosine triphosphate (ATP). Kidney fibrosis develops in response to increased deposition of extracellular matrix (ECM), and up-regulation of collagen I is an early marker of renal disease. With ECM remodeling known to promote a loss of epithelial stability, in the current study we used a clonal human kidney (HK2) model of proximal tubular epithelial cells to determine if collagen I modulates changes in cell function, via connexin-43 (Cx43) hemichannel ATP release. HK2 cells were cultured on collagen I and treated with the beta 1 isoform of the pro-fibrotic cytokine transforming growth factor (TGFβ1) ± the Cx43 mimetic Peptide 5 and/or an anti-integrin α2β1 neutralizing antibody. Phase microscopy and immunocytochemistry observed changes in cell morphology and cytoskeletal reorganization, whilst immunoblotting and ELISA identified changes in protein expression and secretion. Carboxyfluorescein dye uptake and biosensing measured hemichannel activity and ATP release. A Cytoselect extracellular matrix adhesion assay assessed changes in cell-substrate interactions. Collagen I and TGFβ1 synergistically evoked increased hemichannel activity and ATP release. This was paralleled by changes to markers of tubular injury, partly mediated by integrin α2β1/integrin-like kinase signaling. The co-incubation of the hemichannel blocker Peptide 5, reduced collagen I/TGFβ1 induced alterations and inhibited a positive feedforward loop between Cx43/ATP release/collagen I. This study highlights a role for collagen I in regulating connexin-mediated hemichannel activity through integrin α2β1 signaling, ahead of establishing Peptide 5 as a potential intervention.  相似文献   
4.
零压挤出     
Cliff Tubbe 《橡胶工业》2002,49(2):104-105
为满足用户日新月异的需求 ,多年来人们致力于挤出机技术的改进工作。最简单的就是热喂料挤出机 ,它最多只能称作是在一个圆筒内工作的阿基米德螺杆 ,通常用来将没有定型的不连续的胶料制成一定横截面和尺寸均一的连续胶条。但是不能小看这种装置 ,这种古老的热喂料挤出机是很有用的 ,它可以生产轮胎零部件和其它许多工业橡胶制品 ,包括胶带和胶管。至今仍有许多热喂料挤出机在使用中。冷喂料挤出机代替热喂料挤出机有几个很重要的原因 ,其中之一就是热喂料挤出机要求母炼胶充分预热 ,而热炼机费用极为昂贵 ,而且这些价格不菲的庞大装置占地…  相似文献   
5.
With current digital technologies, people have large archives of digital media, such as images and audio files, but there are only limited means to include these media in creative practices of crafting and making. Nevertheless, studies have shown that crafting with digital media often makes these media more cherished and that people enjoy being creative with their digital media. This paper aims to open up the way for novel means for crafting, which include digital media in integrations with physical construction, here called ‘hybrid crafting’. Notions of hybrid crafting were explored to inform the design of products or systems that may support these new crafting practices. We designed ‘Materialise’—a building set that allows for the inclusion of digital images and audio files in physical constructions by using tangible building blocks that can display images or play audio files, alongside a variety of other physical components—and used this set in four hands-on creative workshops to gain insight into how people go about doing hybrid crafting; whether hybrid crafting is desirable; what the characteristics of hybrid crafting are; and how we may design to support these practices. By reflecting on the findings from these workshops, we provide concrete guidelines for the design of novel hybrid crafting products or systems that address craft context, process and result. We aim to open up the design space to designing for hybrid crafting because these new practices provide interesting new challenges and opportunities for future crafting that can lead to novel forms of creative expression.  相似文献   
6.
MeeGo,正在成为移动直联网领域的一颗新星。 在今年2月的世界3GSM大会上,诺基亚与英特尔一起宣布了新一代专门针对移动终端的智能操作平台——MeeGo的诞生。MeeGo是英特尔的Moblin与诺基亚的Maemo的组合体,是为下一代计算设备打造的基于Linux系统的开源软件平台,它完全开放源代码,能够将服务、内容与用户体验相结合,为消费者带来全新的移动互联的操作体验。目前MeeGo由国际非盈利性组织Linux基金会进行管理。  相似文献   
7.
As part of the Bristol Wearable Computing Initiative, we are exploring location-sensing systems suitable for use with wearable computing. In this paper we present our findings, and in particular a wearable application — the ‘Shopping Jacket’ — which relies on a minimal infrastructure to be effective. We use two positioning devices, ‘pingers’ and GPS. The pinger is used to signal the presence of a shop, and to indicate the type of shop and its website. The GPS is used to disambiguate which branch of a high street chain is being passed. The wearable uses this information to determine whether the wearer needs to be alerted that they are passing an interesting shop, or to direct the wearer around a shopping mall. The Shopping Jacket integrates a wearable CardPC, GPS and pinger receivers, a near-field radio link, hand-held display, GSM data telephone and a speech interface into a conventional sports blazer.  相似文献   
8.
A realization problem for a class of linear hereditary systems is formulated and state space representations are constructed from inputoutput relations. The resulting hereditary models are shown to be Euclidean controllable, and comparisons are made between these hereditary realizations and other recently developed theories.This research was supported in part by the Air Force Flight Dynamics Laboratory under grant AFOSR-77-3221.  相似文献   
9.
10.
The propagation of electrical trees is of a particular interest for the power engineering industry as it is one of the major causes for breakdown in high voltage equipments. Composites, materials with barriers and a surrounding polymer matrix are used to extend time to breakdown of the insulations. Since the material, structure or processing of the barriers are various and can determine time to breakdown significantly, the major influences of barriers on the propagation of electrical trees is described in this paper in experiments and numerical simulations. Although it was the motivation, to determine tree growth in the composite structure of mica-epoxy winding insulations, the results can also be used for other composite materials. The trees grew in needle-plane samples and their growth characteristic was optically analysed. The results show that tree propagation can be slowed down when introducing a barrier between the needle and the plane electrode and may cause significantly increased time to breakdown values. The increase depends on the barrier materials used, their thickness, the dielectric strength of the interface to the surrounding epoxy resin and the width of the barrier. When choosing multiple barriers, their arrangement influences time to breakdown significantly. Overlapped barriers show much higher time to breakdown values than impinged ones. From the results, it can be concluded that the selection of the barrier materials, their processing and their arrangement play a major role towards time to breakdown of composite insulation materials.  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