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   3750篇
  免费   473篇
  国内免费   294篇
电工技术   233篇
综合类   425篇
化学工业   64篇
金属工艺   46篇
机械仪表   234篇
建筑科学   308篇
矿业工程   42篇
能源动力   23篇
轻工业   58篇
水利工程   46篇
石油天然气   40篇
武器工业   37篇
无线电   420篇
一般工业技术   456篇
冶金工业   112篇
原子能技术   15篇
自动化技术   1958篇
  2024年   45篇
  2023年   104篇
  2022年   167篇
  2021年   166篇
  2020年   156篇
  2019年   126篇
  2018年   126篇
  2017年   136篇
  2016年   145篇
  2015年   144篇
  2014年   272篇
  2013年   341篇
  2012年   266篇
  2011年   254篇
  2010年   216篇
  2009年   223篇
  2008年   215篇
  2007年   244篇
  2006年   183篇
  2005年   177篇
  2004年   149篇
  2003年   124篇
  2002年   111篇
  2001年   80篇
  2000年   57篇
  1999年   46篇
  1998年   42篇
  1997年   35篇
  1996年   30篇
  1995年   22篇
  1994年   15篇
  1993年   12篇
  1992年   11篇
  1991年   10篇
  1990年   5篇
  1989年   6篇
  1988年   8篇
  1987年   2篇
  1985年   5篇
  1984年   8篇
  1983年   8篇
  1982年   4篇
  1981年   3篇
  1980年   4篇
  1979年   5篇
  1978年   2篇
  1975年   1篇
  1967年   1篇
  1957年   2篇
  1954年   1篇
排序方式: 共有4517条查询结果,搜索用时 109 毫秒
1.
At present, the development and implementation of digital transformation are the keys to promoting high-quality industry development. The new digital fabrication method of robotic 3D printing is a research area being studied by many to tackle the issue of the declining productivity of traditional construction methods. Although many studies have been done, most of the current 3D printing projects are facing limitations in terms of scale. In order to bridge the gap, this article proposed a mass customization 3D printing framework system for large-scale projects. This article discusses how mass customization is made possible through the joint operation of the FUROBOT software and 3D printing hardware. By taking the east gate of Nanjing Happy Valley Plaza as a case study, the article demonstrates and studies the feasibility of the large-scale mass customization 3D printing framework system.  相似文献   
2.
陆斌  何志强 《信息技术》2003,27(7):95-97
交互控制是计算机程序的重要功能 ,也是实现人—机对话的基本途径。VisualBasic编程语言以其易学习掌握、开发灵活的特点而成为目前流行的程序开发工具 ,本文以VisualBasic语言为例介绍了交互控制程序编程方法 ,并对具体的每一种方法编写了相应的示例。  相似文献   
3.
This paper considers the principles of algorithmic and software implementation of the software system NADRA 3D designed to analyze processes in three-dimensional multicomponent soil media. The principles of operation of NADRA 3D are described. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 157–174, November–December 2006.  相似文献   
4.
An alternative approach to understanding innovation is made using two intersecting ideas. The first is that successful innovation requires consideration of the social and organizational contexts in which it is located. The complex context of construction work is characterized by inter-organizational collaboration, a project-based approach and power distributed amongst collaborating organizations. The second is that innovations can be divided into two modes: 'bounded', where the implications of innovation are restricted within a single, coherent sphere of influence, and 'unbounded', where the effects of implementation spill over beyond this. Bounded innovations are adequately explained within the construction literature. However, less discussed are unbounded innovations, where many firms' collaboration is required for successful implementation, even though many innovations can be considered unbounded within construction's inter-organizational context. It is argued that unbounded innovations require an approach to understand and facilitate the interactions both within a range of actors and between the actors and technological artefacts. The insights from a sociology of technology approach can be applied to the multiplicity of negotiations and alignments that constitute the implementation of unbounded innovation. The utility of concepts from the sociology of technology, including 'system building' and 'heterogeneous engineering', is demonstrated by applying them to an empirical study of an unbounded innovation on a major construction project (the new terminal at Heathrow Airport, London, UK). This study suggests that 'system building' contains outcomes that are not only transformations of practices, processes and systems, but also the potential transformation of technologies themselves.  相似文献   
5.
We have previously investigated effects of radiation levels on power quality of a number PV-grid interactive systems in Thailand, in terms of harmonics and voltage variation at the point of common coupling (PCC). In this paper, we focus on the nature of components of complex power (actual, reactive and apparent power) of inverter output of a PV-grid interactive system due to low radiation, below 400 W/m2. The system being investigated has an array of 4.2 kWp and representative of roof top units. It is observed that a PV array supplies increasing real power, in magnitude and as percentage of complex power, at high values of radiation. At low radiation level when the array does not provide enough output power, reactive power is drawn from distribution transformer and fed into an inverter and loads. Based on results from the test site and long term radiation data of Bangkok, we then estimate energy available from low radiation from a hypothetical PV-grid interactive unit in Bangkok of a similar size. It can be seen that for a tropical climate like Thailand a significant amount of energy, 20–30% of radiation energy, is in the form of reactive power. Methods must be devised to capture this low radiation energy and converted into real power form.  相似文献   
6.
Curry I. Guinn 《Knowledge》1994,7(4):277-278
Collaboration is more efficient when the most capable participant for each goal has initiative in directing the problem-solving for that goal. The paper describes a method for using a probabilistic analysis to create a mode-switching mechanism that selects which participant should control the collaborative problem solving so that efficiency is maximized.  相似文献   
7.
试论就业形势与战略   总被引:5,自引:1,他引:4  
论述了就业的特殊重要性、目前我国就业形势的极端严重性,以及所应当采取的战略和措施。  相似文献   
8.
基于CORBA和WEB的产品数据管理体系结构研究   总被引:2,自引:0,他引:2       下载免费PDF全文
 产品数据管理(product data management,PDM)作为产品信息管理集成框架,已成为当前研究开发型企业提高其核心竞争力的一种重要竞争策略.介绍了PDM技术的起源与发展,阐述了PDM的应用功能框架.结合当今软件技术的发展,分析了基于CORBA和WEB技术的PDM/CPC代表性产品Windchill平台的体系结构,指出了传统PDM过渡到CPC的必然发展趋势.  相似文献   
9.
Trust for Ubiquitous,Transparent Collaboration   总被引:1,自引:0,他引:1  
Shand  Brian  Dimmock  Nathan  Bacon  Jean 《Wireless Networks》2004,10(6):711-721
In this paper, trust-based recommendations control the exchange of personal information between handheld computers. Combined with explicit risk analysis, this enables unobtrusive information exchange, while limiting access to confidential information. The same model can be applied to a wide range of mobile computing tasks, such as managing personal address books and electronic diaries, to automatically provide an appropriate level of security. Recommendations add structure to the information, by associating categories with data and with each other, with degrees of trust belief and disbelief. Since categories also in turn confer privileges and restrict actions, they are analogous to rôles in a Rôle-Based Access Control system, while principals represent their trust policies in recommendations. Participants first compute their trust in information, by combining their own trust assumptions with others' policies. Recommendations are thus linked together to compute a considered, local trust assessment. Actions are then moderated by a risk assessment, which weighs up costs and benefits, including the cost of the user's time, before deciding whether to allow or forbid the information exchange, or ask for help. By unifying trust assessments and access control, participants can take calculated risks to automatically yet safely share their personal information.  相似文献   
10.
多媒体课件在开放实验室中的应用   总被引:2,自引:0,他引:2  
介绍了制作多媒体课件的必要性,及所制作课件的特点。该课件与实验室管理系统配合起来,有利于实现实验室的全面开放。  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