全文获取类型
收费全文 | 3289篇 |
免费 | 386篇 |
国内免费 | 363篇 |
专业分类
电工技术 | 200篇 |
技术理论 | 1篇 |
综合类 | 454篇 |
化学工业 | 61篇 |
金属工艺 | 27篇 |
机械仪表 | 133篇 |
建筑科学 | 75篇 |
矿业工程 | 25篇 |
能源动力 | 29篇 |
轻工业 | 45篇 |
水利工程 | 22篇 |
石油天然气 | 23篇 |
武器工业 | 78篇 |
无线电 | 768篇 |
一般工业技术 | 255篇 |
冶金工业 | 35篇 |
原子能技术 | 11篇 |
自动化技术 | 1796篇 |
出版年
2024年 | 7篇 |
2023年 | 26篇 |
2022年 | 47篇 |
2021年 | 48篇 |
2020年 | 75篇 |
2019年 | 81篇 |
2018年 | 66篇 |
2017年 | 89篇 |
2016年 | 112篇 |
2015年 | 135篇 |
2014年 | 184篇 |
2013年 | 283篇 |
2012年 | 272篇 |
2011年 | 255篇 |
2010年 | 209篇 |
2009年 | 245篇 |
2008年 | 270篇 |
2007年 | 246篇 |
2006年 | 232篇 |
2005年 | 201篇 |
2004年 | 138篇 |
2003年 | 158篇 |
2002年 | 87篇 |
2001年 | 92篇 |
2000年 | 55篇 |
1999年 | 59篇 |
1998年 | 39篇 |
1997年 | 32篇 |
1996年 | 41篇 |
1995年 | 41篇 |
1994年 | 46篇 |
1993年 | 28篇 |
1992年 | 19篇 |
1991年 | 22篇 |
1990年 | 28篇 |
1989年 | 10篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1973年 | 2篇 |
1960年 | 1篇 |
1959年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有4038条查询结果,搜索用时 15 毫秒
41.
Maintenance-related costs are one of the main components of overhead costs and constitute an important part of a product’s actual cost. Therefore, making proper efforts to reduce and optimise maintenance costs could be one way of gaining competitive advantages. A major part of maintenance-related costs is the salaries paid to the workforce in the maintenance department. This paper seeks the optimal assignment of human resources to the maintenance department to reduce the related costs. First, we model the maintenance department using fuzzy queue models. Then, a cost function is proposed which includes the costs of workforce shortage and workforce overload. The optimal size of workforce is obtained by considering different numbers and choosing the one which minimises the total costs. Some parameters are fuzzy outputs of the queue models, which make fuzzy results of the cost function. In order to find the minimum fuzzy cost function, we use Lee and Li fuzzy ranking method. Finally, our model is tested in a spiral-tube company and a sensitivity analysis is performed. 相似文献
42.
A differential improvement modification to Hybrid Genetic Algorithms is proposed. The general idea is to perform more extensive improvement algorithms on higher quality solutions. Our proposed Differential Improvement (DI) approach is of rather general character. It can be implemented in many different ways. The paradigm remains invariant and can be easily applied to a wider class of optimization problems. Moreover, the DI framework can also be used within other Hybrid metaheuristics like Hybrid Scatter Search algorithms, Particle Swarm Optimization, or Bee Colony Optimization techniques. 相似文献
43.
In the process of Research and Development (R&D) project selection, experts play an important role because their opinions are the foundation on which to judge the potential value of a project. How to assign the most appropriate experts to review project proposals might greatly affect the quality of project selection, which in turn could affect the return on investment of the funding organization. However, in many funding organizations, current approaches to assigning reviewers are still based on simply matching the discipline area of the reviewers with that of the proposal, which could result in poor quality of project selection and poor future financial return. Additionally, these approaches might make it difficult to balance resources and resolve conflicts of interests between reviewers and applicants. Therefore, to overcome these problems, there is an urgent need for a systematic approach to support and automate the reviewer assignment process. This research aims at proposing an intelligent decision support approach for reviewer assignment and developing an Assignment Decision Support System (ADSS). In this approach, heuristic knowledge of expert assignment and techniques of operations research are integrated. The approach uses decision models to determine the best solution of reviewer assignment that maximizes the total expertise level of the reviewers assigned to proposals. It also balances the distribution of proposals at different grades and solves conflicts of interests between reviewers and applicants. Its application in the National Natural Science Foundation of China (NSFC) and the computational results of its effectiveness and efficiency are also described. 相似文献
44.
安博林 《化工自动化及仪表》2016,(5)
通过设计一个比例微分控制律u=K0(θ)q+K1(θ)q来对二阶线性变参系统q-A(θ)qC(θ)q=B(θ)u进行特征结构配置,其中状态空间矩阵[A(θ)B(θ)]取决于一系列在线可测的时变参数,同时为上述特征结构配置问题的解决提供了一种新的拥有最大设计自由度的参数化方法。该方法主要的计算量在于两组矩阵的初等变换,而且在选择一些合适的闭环特征值的前提下,实际计算仅涉及到一系列奇异值分解。同时,由于该方法直接应用原有二阶变参系统的系数矩阵A(θ)、B(θ)和C(θ),因此大多数的计算主要针对n维矩阵。最后针对航天器在轨加油姿态系统控制的仿真验证了该方法的有效性和实用性。 相似文献
45.
46.
47.
48.
针对DSP上低码率语音编码器的实现和优化问题,研究了片上Cache的分配策略.根据指令Cache的大小,以及程序处理的数据量的大小,将程序分成大小合理的段,分阶段载入Cache中.对数据Cache的分配考虑了Cache结构和数据本身的特点,使有限的数据Cache得到充分的利用.全面考察数据的生命期,使已经载入数据Cac... 相似文献
49.
50.
探讨和分析了时钟同步网指标和移动基站指标,结合本地网时间指标的分析,尝试给出了IP环境下同步网模型和指标分配。讨论的重点是时钟同步网,并在一定程度上论述了时间同步网。 相似文献