全文获取类型
收费全文 | 5853篇 |
免费 | 251篇 |
国内免费 | 269篇 |
专业分类
电工技术 | 145篇 |
技术理论 | 10篇 |
综合类 | 270篇 |
化学工业 | 98篇 |
金属工艺 | 36篇 |
机械仪表 | 136篇 |
建筑科学 | 1142篇 |
矿业工程 | 92篇 |
能源动力 | 92篇 |
轻工业 | 25篇 |
水利工程 | 2755篇 |
石油天然气 | 146篇 |
武器工业 | 11篇 |
无线电 | 130篇 |
一般工业技术 | 196篇 |
冶金工业 | 402篇 |
原子能技术 | 26篇 |
自动化技术 | 661篇 |
出版年
2024年 | 5篇 |
2023年 | 33篇 |
2022年 | 59篇 |
2021年 | 59篇 |
2020年 | 117篇 |
2019年 | 80篇 |
2018年 | 111篇 |
2017年 | 120篇 |
2016年 | 121篇 |
2015年 | 138篇 |
2014年 | 390篇 |
2013年 | 419篇 |
2012年 | 347篇 |
2011年 | 523篇 |
2010年 | 310篇 |
2009年 | 321篇 |
2008年 | 306篇 |
2007年 | 345篇 |
2006年 | 343篇 |
2005年 | 369篇 |
2004年 | 287篇 |
2003年 | 291篇 |
2002年 | 244篇 |
2001年 | 165篇 |
2000年 | 151篇 |
1999年 | 174篇 |
1998年 | 154篇 |
1997年 | 117篇 |
1996年 | 80篇 |
1995年 | 60篇 |
1994年 | 39篇 |
1993年 | 15篇 |
1992年 | 20篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 13篇 |
1985年 | 3篇 |
1984年 | 10篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1966年 | 6篇 |
1964年 | 1篇 |
排序方式: 共有6373条查询结果,搜索用时 15 毫秒
1.
High dimensionality in real-world multi-reservoir systems greatly hinders the application and popularity of evolutionary algorithms, especially for systems with heterogeneous units. An efficient hierarchical optimization framework is presented for search space reduction, determining the best water distributions, not only between cascade reservoirs, but also among different types of hydropower units. The framework is applied to the Three Gorges Project (TGP) system and the results demonstrate that the difficulties of multi-reservoir optimization caused by high dimensionality can be effectively solved by the proposed hierarchical method. For the day studied, power output could be increased by 6.79 GWh using an optimal decision with the same amount of water actually used; while the same amount of power could be generated with 2.59 × 107 m3 less water compared to the historical policy. The methodology proposed is general in that it can be used for other reservoir systems and other types of heterogeneous unit generators. 相似文献
2.
通过分析A公司在研发项目范围管理中所存在问题,提出研发项目范围管理的方法及其在C产品的应用实例,通过运用研发项目范围管理的工具和方法,改善产品开发流程,从而缩短新产品开发周期,提高响应市场的速度,并提高企业研发项目的管理能力。 相似文献
3.
《International Journal of Project Management》2020,38(1):27-35
26 interviews were conducted with a snowball sample of project managers to explore how project managers were influenced by accountability arrangements and how they responded to accountability demands. Using a grounded theory approach to code the interview data, this study revealed that project managers develop new skills to respond to accountability demands. These effects are facilitated by the interaction of resource-based mechanisms and reflexivity that interact with the contextual factors of the project. The study broadens the understanding of accountability in project management and suggests a model for further empirical examination. 相似文献
4.
随着BIM技术的进步,建筑行业越来越重视BIM技术的应用,并在应用过程中取得一定的成效。本文从工程造价决策、设计、招投标、施工、竣工五个阶段阐述BIM技术在建筑工程造价中的应用对策。 相似文献
5.
《International Journal of Project Management》2020,38(7):429-440
Agile practices become increasingly popular for projects and project portfolios offering firms a higher flexibility to adapt to dynamic environments. This study investigates the antecedents and consequences of agile practices' relevance for strategy formulation in project portfolio management processes. Building on complex adaptive systems theory, we hypothesize a positive relationship between agile capabilities and emerging strategy initiatives and eventually portfolio success. Agile capabilities refer to both the project portfolio organization's intensity of and competence in applying agile practices. Using a sample of 135 portfolios and multiple informants for each portfolio, the results support entrepreneurial orientation and voice behavior as antecedents for agile capabilities. Furthermore, the findings support an agile portfolio's positive relationship with emergence recognition and overall portfolio success. The findings contribute to the literature by identifying two significant antecedents of agile capabilities as well as empirically demonstrating the positive relationship between agile portfolios and emerging strategy recognition. For practitioners, the study encourages the application of agile practices by stressing the general positive influence of agile capabilities and underlines entrepreneurial orientation and voice behavior as important methods of empowerment for agile portfolio processes. 相似文献
6.
Risk allocation decisions are of critical importance in project management. The present study proposes an explanation for how risk allocation in a contract motivates a contractor to cooperate with a project owner. Theories of risk allocation and trust were used to motivate the research. Using a survey methodology, we collected data concerning 124 construction projects in China. We found that risk allocation influenced the contractor’s role behavior through the contractor’s feeling of being trusted but not the contractor’s trust in the owner. Feeling of being trusted partially mediated the effect of risk allocation on the contractor’s in-role (i.e., contractual) behavior and fully mediated the effect on extra-role behavior. The study introduces a social and psychological view of the impacts of risk allocation to the project and engineering management literature. We contribute to theory by arguing and demonstrating the mediating effect of trust on the relationship between risk allocation and contractor behavior. From a practical standpoint, we conclude that contractual risk allocation has a significant impact on building a trusting relationship between owners and contractors and that contractors who feel trusted perform both contractually mandated actions and actions external to the contract more diligently, resulting in the likelihood of improved outcomes for both parties. 相似文献
7.
8.
三峡三期工程主坝大体积混凝土内部温度控制 总被引:2,自引:2,他引:0
三峡右岸三期工程施工中,为了有效控制坝体大体积混凝土内部温升,采取了高温季节使用预冷混凝土浇筑、控制混凝土出机口温度及浇筑温度、对混凝土内部人工通水进行初冷、中冷和后冷等措施。三峡三期工程大坝混凝土内部温度没有出现超标现象,混凝土温控工作取得了良好的效果。 相似文献
9.
本文介绍了广东省智能网的组网方案及所能提供的业务,并论述了智能网工程建设,安装维护以及与广东省现有移动通信网联网中存在的一些问题。 相似文献
10.
威海市污水处理深海排放工程是为改善其水域环境而建设的一英包括市区排水系统,污水预处理厂,输水管道和海洋放流管系统在内的完整而典型的工程,因此其工程设计扣的经验将会对同类项目的设计与工程建设有所借鉴。 相似文献