全文获取类型
收费全文 | 327687篇 |
免费 | 29629篇 |
国内免费 | 18536篇 |
专业分类
电工技术 | 27821篇 |
技术理论 | 51篇 |
综合类 | 42479篇 |
化学工业 | 39294篇 |
金属工艺 | 13567篇 |
机械仪表 | 17705篇 |
建筑科学 | 41960篇 |
矿业工程 | 17174篇 |
能源动力 | 10701篇 |
轻工业 | 17613篇 |
水利工程 | 15912篇 |
石油天然气 | 14301篇 |
武器工业 | 3323篇 |
无线电 | 22351篇 |
一般工业技术 | 25862篇 |
冶金工业 | 18599篇 |
原子能技术 | 3977篇 |
自动化技术 | 43162篇 |
出版年
2024年 | 1189篇 |
2023年 | 3640篇 |
2022年 | 6886篇 |
2021年 | 8253篇 |
2020年 | 8936篇 |
2019年 | 7598篇 |
2018年 | 7214篇 |
2017年 | 8828篇 |
2016年 | 9997篇 |
2015年 | 10987篇 |
2014年 | 18834篇 |
2013年 | 18036篇 |
2012年 | 22196篇 |
2011年 | 23574篇 |
2010年 | 18366篇 |
2009年 | 19205篇 |
2008年 | 17992篇 |
2007年 | 22937篇 |
2006年 | 21506篇 |
2005年 | 18616篇 |
2004年 | 15864篇 |
2003年 | 14152篇 |
2002年 | 11711篇 |
2001年 | 9910篇 |
2000年 | 8403篇 |
1999年 | 7001篇 |
1998年 | 5284篇 |
1997年 | 4569篇 |
1996年 | 4158篇 |
1995年 | 3540篇 |
1994年 | 3189篇 |
1993年 | 2379篇 |
1992年 | 2072篇 |
1991年 | 1549篇 |
1990年 | 1365篇 |
1989年 | 1200篇 |
1988年 | 945篇 |
1987年 | 660篇 |
1986年 | 496篇 |
1985年 | 417篇 |
1984年 | 377篇 |
1983年 | 270篇 |
1982年 | 249篇 |
1981年 | 183篇 |
1980年 | 147篇 |
1979年 | 126篇 |
1978年 | 68篇 |
1977年 | 76篇 |
1975年 | 62篇 |
1959年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Jean-Claude Malela-Majika Sandile Charles Shongwe Olatunde Adebayo Adeoti 《Quality and Reliability Engineering International》2021,37(8):3314-3322
The sensitivity of a monitoring scheme depends on many factors including the variance of the charting statistic which is very important in the computation of the control limits. This paper discusses the computation of the variance of the recently proposed hybrid homogeneously weighted moving average (HHWMA) scheme which was based on an incorrect assumption. The correct variance is used to evaluate the run-length characteristics of the HHWMA scheme. It is observed that the incorrect variance has a significant impact on the sensitivity (or performance) of the HHWMA scheme. 相似文献
2.
Structural health monitoring system based on multi-agent coordination and fusion for large structure
In practical applications of structural health monitoring technology, a large number of distributed sensors are usually adopted to monitor the big dimension structures and different kinds of damage. The monitored structures are usually divided into different sub-structures and monitored by different sensor sets. Under this situation, how to manage the distributed sensor set and fuse different methods to obtain a fast and accurate evaluation result is an important problem to be addressed deeply. In the paper, a multi-agent fusion and coordination system is presented to deal with the damage identification for the strain distribution and joint failure in the large structure. Firstly, the monitoring system is adopted to distributedly monitor two kinds of damages, and it self-judges whether the static load happens in the monitored sub-region, and focuses on the static load on the sub-region boundary to obtain the sensor network information with blackboard model. Then, the improved contract net protocol is used to dynamically distribute the damage evaluation module for monitoring two kinds of damage uninterruptedly. Lastly, a reliable assessment for the whole structure is given by combing various heterogeneous classifiers strengths with voting-based fusion. The proposed multi-agent system is illustrated through a large aerospace aluminum plate structure experiment. The result shows that the method can significantly improve the monitoring performance for the large-scale structure. 相似文献
3.
The proliferating need for sustainability intervention in food grain transportation planning is anchoring the attention of researchers in the interests of stakeholders and environment at large. Uncertainty associated with food grain supply further intensifies the problem steering the need for designing robust, cost-efficient and sustainable models. In line with this, this paper aims to develop a robust and sustainable intermodal transportation model to facilitate single type of food grain commodity shipments while considering procurement uncertainty, greenhouse gas emissions, and intentional hub disruption. The problem is designed as a mixed integer non-linear robust optimisation model on a hub and spoke network for evaluating near optimal shipment quantity, route selection and hub location decisions. The robust optimisation approach considers minimisation of total relative regret associated with total cost subject to several real-time constraints. A version of Particle Swarm Optimisation with Differential Evolution is proposed to tackle the resulting NP-hard problem. The model is tested with two other state-of the art meta-heuristics for small, medium, and large datasets subject to different procurement scenarios inspired from real time food grain operations in Indian context. Finally, the solution is evaluated with respect to total cost, model and solution robustness for all instances. 相似文献
4.
5.
本文以云杉八齿小蠹Ips typographus Linnaeus为例,经标本选取,观察虫体整体形态,绘制整体结构草图,电子显微镜观察局部、得到局部数字图像,分别建立虫体每一部分的高精度细节。把模型每部分拼装在一起组成整体模型,构建出了云杉八齿小蠹三维虚拟昆虫数字化模型。 相似文献
6.
7.
8.
9.
10.
A small handful of recent studies have addressed a phenomenon known as “phantom vibration syndrome”. This refers to when phone users perceive their device to vibrate, indicating that a call or text is incoming, when in fact the phone did not vibrate at all. Though these studies show that most users do not find phantom vibration hallucinations to be very bothersome, they also find that a large majority of users experience this phenomenon. This paper explores what the striking prevalence of phantom vibration syndrome means for our contemporary relationships with technology. I begin with a review of the theories purporting to explain these data, which largely rely on particular understandings of the brain. Next I develop an alternative theory of phantom vibration syndrome based on insights from the philosophical tradition of phenomenology. This account considers the ways users develop bodily and perceptual habits regarding how the phone is understood and used. By critically contrasting these different theories, we can refine our questions about what the high prevalence of phantom vibration syndrome implies about our contemporary technological situation. 相似文献