全文获取类型
收费全文 | 66167篇 |
免费 | 8077篇 |
国内免费 | 4429篇 |
专业分类
电工技术 | 10023篇 |
技术理论 | 1篇 |
综合类 | 5837篇 |
化学工业 | 4033篇 |
金属工艺 | 5685篇 |
机械仪表 | 5397篇 |
建筑科学 | 2629篇 |
矿业工程 | 1329篇 |
能源动力 | 2068篇 |
轻工业 | 1655篇 |
水利工程 | 1236篇 |
石油天然气 | 1622篇 |
武器工业 | 805篇 |
无线电 | 19207篇 |
一般工业技术 | 6115篇 |
冶金工业 | 1974篇 |
原子能技术 | 806篇 |
自动化技术 | 8251篇 |
出版年
2024年 | 299篇 |
2023年 | 969篇 |
2022年 | 1497篇 |
2021年 | 1898篇 |
2020年 | 2010篇 |
2019年 | 1749篇 |
2018年 | 1603篇 |
2017年 | 2148篇 |
2016年 | 2257篇 |
2015年 | 2567篇 |
2014年 | 3818篇 |
2013年 | 3858篇 |
2012年 | 4774篇 |
2011年 | 4738篇 |
2010年 | 3747篇 |
2009年 | 3794篇 |
2008年 | 4058篇 |
2007年 | 4576篇 |
2006年 | 4168篇 |
2005年 | 3539篇 |
2004年 | 3147篇 |
2003年 | 2780篇 |
2002年 | 2291篇 |
2001年 | 2143篇 |
2000年 | 1714篇 |
1999年 | 1558篇 |
1998年 | 1177篇 |
1997年 | 1064篇 |
1996年 | 911篇 |
1995年 | 767篇 |
1994年 | 716篇 |
1993年 | 576篇 |
1992年 | 488篇 |
1991年 | 392篇 |
1990年 | 279篇 |
1989年 | 173篇 |
1988年 | 132篇 |
1987年 | 49篇 |
1986年 | 43篇 |
1985年 | 42篇 |
1984年 | 38篇 |
1983年 | 15篇 |
1982年 | 12篇 |
1981年 | 17篇 |
1980年 | 12篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1976年 | 8篇 |
1975年 | 13篇 |
1959年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Output feedback controller for polytopic systems exploiting the direct searching of the design space
This paper deals with the problem of designing a robust static output feedback controller for polytopic systems. The current research that tackled this problem is mainly based on LMI method, which is conservative by nature. In this paper, a novel approach is proposed, which considers the design space of the controller parameters and iteratively partitions the space to small simplexes. Then, by assessing the stability in each simplex, the solution space for design parameters is directly determined. It has been theoretically proved that, if there exists a feasible solution in the design space, the algorithm can find it. To validate the result of the proposed approach, comparative simulation examples are given to illustrate the performance of the design methodology as compared to those of previous approaches. 相似文献
23.
Yigit Kazancoglu 《国际生产研究杂志》2020,58(14):4246-4266
End of life (EOL) phase of a product is receiving more attention due to increase in environmental concerns, and many studies have been conducted for value creation in EOL, focusing on concepts as remanufacturing, reuse and recycling in sustainable production manner. This study especially focuses on one of global problem, e-waste. To minimise the amount of wastes and maximise recovered materials from EOL, disassembly is one of the most important concept, associated with reuse, and balancing disassembly line in an optimal way is essential for organisations. In disassembly line balancing (DLB), not only precedence of tasks, but also risk criteria related to environment and human safety should be considered for sustainability. The aim of this study is to propose a model based on triple bottom line (TBL) dimensions, i.e. human safety, environmental safety and business criteria. To achieve sustainability in DLB, and for risk assessment in sustainable DLB, it had been decided to use a multi-criteria method, i.e. TODIM, acronym in Portuguese of ‘Tomada de Decisão Iterativa Multicritério’. The proposed model included 22 disassembly criteria categorised under TBL dimensions, which are derived from the literature. Implementation of the study was conducted for computer disassembly processes, and as a result of the study approximately 12% an improvement in cycle time was succeeded. In the long run, the integration of sustainability in disassembly operations may contribute to the competitive advantage of the company in terms of differentiation and corporate image by achieving business, environment and human targets simultaneously. 相似文献
24.
Number entry is a ubiquitous activity and is often performed in safety- and mission-critical procedures, such as healthcare, science, finance, aviation and in many other areas. We show that Monte Carlo methods can quickly and easily compare the reliability of different number entry systems. A surprising finding is that many common, widely used systems are defective, and induce unnecessary human error. We show that Monte Carlo methods enable designers to explore the implications of normal and unexpected operator behaviour, and to design systems to be more resilient to use error. We demonstrate novel designs with improved resilience, implying that the common problems identified and the errors they induce are avoidable. 相似文献
25.
This paper presents a fast distance relay for series compensated transmission lines based on the R–L differential-equation algorithm using the theory of equal transfer process of transmission lines. The measuring distances based on the proposed algorithm can fast approach the actual value of fault distance when a fault occurs in front of the series capacitor. When a fault occurs behind of the series capacitor, the fault loop, including the series capacitor, does not match the R–L transmission line model, so the measuring distances fluctuate severely. Based on this, the relative position of the fault with respect to the series capacitor can be judged effectively according to the fluctuation range of the measuring distances, and the accurate fault location can be obtained fast. A variety of PSCAD/EMTDC simulation tests show that the new relay has fast operating speed and high accuracy when applied to the long series compensated transmission lines. 相似文献
26.
27.
ABSTRACTThis paper deals with asymptotic stabilisation of a class of nonlinear input-delayed systems via dynamic output feedback in the presence of disturbances. The proposed strategy has the structure of an observer-based control law, in which the observer estimates and predicts both the plant state and the external disturbance. A nominal delay value is assumed to be known and stability conditions in terms of linear matrix inequalities are derived for fast-varying delay uncertainties. Asymptotic stability is achieved if the disturbance or the time delay is constant. The controller design problem is also addressed and a numerical example with an unstable system is provided to illustrate the usefulness of the proposed strategy. 相似文献
28.
冯鹏一 《信息通信技术与政策》2020,(1):12-15
以电信用户入网协议为切入点,电信用户的携号转网行为应受到《合同法》《消费者权益保护法》等私法规范的保护与限制。该行为引起的格式条款解释、合同终止、违约责任、损失赔偿等问题,不能仅靠《电信条例》等公法规范来调整。应当积极引导广大消费者用户以私法领域相关规定为依据,转变争议解决思维,拓宽纠纷处理途径,合理选择维权手段,以保护自身合法民事权益,与行业监管部门共同推动电信行业有序发展。 相似文献
29.
Serena Finco Daria Battini Xavier Delorme Alessandro Persona Fabio Sgarbossa 《国际生产研究杂志》2020,58(4):1255-1270
Ergonomic aspects have a crucial role in manual assembly systems. They impact on the workers’ health, final product quality and productivity. For these reasons, there is the necessity to integrate them into the assembly line balancing phase as, whereas, only time and cost variables are considered. In this study, human energy expenditures are considered as ergonomic aspects and we integrate them, for the first time, into the assembly line balancing problem type 2 through the rest allowance evaluation. We consider as an objective function the minimization of the smoothness index. Firstly, a new optimal method based on mixed integer linear programming and a new linearization methodology are proposed. Then, a heuristic approach is introduced. To complete the study, a computational experimentation is presented to validate the mathematical model and to compare the methodologies proposed in terms of computational time, complexity and solution. Additionally, we provide a detailed analysis of the impact that rest allowance evaluation can have on productivity comparing the results obtained, taking into account the rest allowance integration before, during and after the assembly balancing process. 相似文献