全文获取类型
收费全文 | 70079篇 |
免费 | 3596篇 |
国内免费 | 2385篇 |
专业分类
电工技术 | 5608篇 |
技术理论 | 19篇 |
综合类 | 7878篇 |
化学工业 | 2395篇 |
金属工艺 | 832篇 |
机械仪表 | 2959篇 |
建筑科学 | 13097篇 |
矿业工程 | 3039篇 |
能源动力 | 1892篇 |
轻工业 | 1851篇 |
水利工程 | 4243篇 |
石油天然气 | 1760篇 |
武器工业 | 302篇 |
无线电 | 5779篇 |
一般工业技术 | 3438篇 |
冶金工业 | 4915篇 |
原子能技术 | 454篇 |
自动化技术 | 15599篇 |
出版年
2024年 | 104篇 |
2023年 | 449篇 |
2022年 | 945篇 |
2021年 | 1316篇 |
2020年 | 1455篇 |
2019年 | 989篇 |
2018年 | 920篇 |
2017年 | 1281篇 |
2016年 | 1631篇 |
2015年 | 1837篇 |
2014年 | 5758篇 |
2013年 | 4529篇 |
2012年 | 5058篇 |
2011年 | 5446篇 |
2010年 | 4180篇 |
2009年 | 4512篇 |
2008年 | 4526篇 |
2007年 | 5500篇 |
2006年 | 4766篇 |
2005年 | 4056篇 |
2004年 | 3511篇 |
2003年 | 3120篇 |
2002年 | 2474篇 |
2001年 | 1802篇 |
2000年 | 1399篇 |
1999年 | 1044篇 |
1998年 | 715篇 |
1997年 | 533篇 |
1996年 | 423篇 |
1995年 | 359篇 |
1994年 | 266篇 |
1993年 | 198篇 |
1992年 | 134篇 |
1991年 | 106篇 |
1990年 | 68篇 |
1989年 | 93篇 |
1988年 | 72篇 |
1987年 | 35篇 |
1986年 | 68篇 |
1985年 | 73篇 |
1984年 | 74篇 |
1983年 | 82篇 |
1982年 | 24篇 |
1981年 | 19篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1977年 | 14篇 |
1975年 | 6篇 |
1961年 | 7篇 |
1959年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
Penedo Frank J.; Dahn Jason R.; Gonzalez Jeffrey S.; Molton Ivan; Carver Charles S.; Antoni Michael H.; Roos Bernard A.; Schneiderman Neil 《Canadian Metallurgical Quarterly》2003,22(2):220
This study evaluated relations among optimism, perceived stress management skills (PSMS), and positive mood in 46 men who had surgical treatment for localized prostate cancer. The authors found that optimism, PSMS, and positive mood scores were positively correlated. Positive mood was unrelated to demographic and disease-related control variables. In a hierarchical regression model controlling for PSMS, the relationship between optimism and positive mood became nonsignificant, whereas PSMS remained a correlate of positive mood. Results suggest that the relationship between optimism and positive mood may be mediated by belief in being able to use stress management techniques effectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
介绍了房地产企业项目进度控制的重要性,从事前、事中、事后三个阶段探讨了工程进度的控制,以保证房地产企业的项目顺利完工,从而保证建筑物的施工质量,提高房地产企业的竞争力。 相似文献
24.
基于清单计价模式的工程项目投资控制 总被引:2,自引:0,他引:2
从使用清单计价模式的必要性出发,分析了目前国内清单计价模式存在的问题,探讨了清单计价模式对工程项目投资控制的影响,并重点指出如何在工程项目各个不同的阶段通过清单计价的方式来控制工程项目投资成本,降低工程项目的投资风险。 相似文献
25.
加强和改善公路施工企业项目管理的途径 总被引:2,自引:1,他引:1
对我国工程项目管理的特点及其内容进行了介绍,提出了当前施工项目管理工作中存在的问题,并针对出现的问题阐述了加强和改善公路工程施工企业项目管理的途径,使项目管理水平能上一个新台阶。 相似文献
26.
结合工程概况及工程特点,从机械设备配置、劳动力组织、现场管理等方面介绍了大窝山隧道进口Ⅱ级,Ⅲ级围岩段的快速掘进施工组织与管理措施,为类似隧道的快速掘进施工组织与管理提拱了相关经验. 相似文献
27.
Chris Harty 《Building Research & Information》2005,33(6):512-522
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
28.
3-D MCM封装技术及其应用 总被引:1,自引:0,他引:1
介绍了超大规模集成电路(VLSI)用的3-D MCM封装技术的最新发展,重点介绍了3-D MCM封装垂直互连工艺,分析了3-D MCM封装技术的硅效率、复杂程度、热处理、互连密度、系统功率与速度等问题,并对3-D MCM封装的应用作了简要说明。 相似文献
29.
Rudolf Habison 《International Journal of Project Management》1985,3(3):178-181
Meeting time and cost objectives in complex projects involves specific problems and risks. An attempt is made to analyse the components of total cost increase of a project caused by time delay. An outline is given as to how these considerations can be used to estimate cost increases in investors' decision situations as well as to ascertain fair contractual penalties and claims for compensation and for the evaluation of justified project acceleration costs. 相似文献
30.
Central to cost-based competition is the capability to accurately predict the cost of delivering a project. Most literature on cost estimation focuses on specific estimation methods as generic techniques and little attention has been paid to the unique requirements at each project stage. This note attempts to identify the critical factors for effective estimation at various stages of typical construction projects. Drawing from organization control theory and cost estimating literature, this note develops a theoretical framework that identifies the critical factors for effective cost estimation during each project phase of a conventional construction project. The underlying logic is that as a cost estimating effort progresses, both task programmability and output measurability improve. As a result, control effort will shift from input-oriented control to a combination of output and behavior control. 相似文献