全文获取类型
收费全文 | 770篇 |
免费 | 56篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 11篇 |
综合类 | 4篇 |
化学工业 | 177篇 |
金属工艺 | 31篇 |
机械仪表 | 22篇 |
建筑科学 | 37篇 |
矿业工程 | 2篇 |
能源动力 | 62篇 |
轻工业 | 53篇 |
水利工程 | 3篇 |
石油天然气 | 15篇 |
无线电 | 66篇 |
一般工业技术 | 174篇 |
冶金工业 | 52篇 |
原子能技术 | 10篇 |
自动化技术 | 109篇 |
出版年
2023年 | 11篇 |
2022年 | 20篇 |
2021年 | 62篇 |
2020年 | 21篇 |
2019年 | 30篇 |
2018年 | 40篇 |
2017年 | 40篇 |
2016年 | 40篇 |
2015年 | 27篇 |
2014年 | 34篇 |
2013年 | 67篇 |
2012年 | 56篇 |
2011年 | 42篇 |
2010年 | 41篇 |
2009年 | 43篇 |
2008年 | 29篇 |
2007年 | 32篇 |
2006年 | 18篇 |
2005年 | 12篇 |
2004年 | 12篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1971年 | 7篇 |
1967年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有828条查询结果,搜索用时 203 毫秒
21.
分析了特征选择采用互信息方法时文本分类性能较低的原因,认为与其在特征选择时倾向于选择稀有特征这一缺陷有很大关系。在此基础上,提出了一种基于分散度和平均频度的互信息特征选择方法。实验结果表明,改进后的互信息方法使文本分类性能有明显提高。 相似文献
22.
23.
Ayse Tosun Oscar Dieste Davide Fucci Sira Vegas Burak Turhan Hakan Erdogmus Adrian Santos Markku Oivo Kimmo Toro Janne Jarvinen Natalia Juristo 《Empirical Software Engineering》2017,22(6):2763-2805
Existing empirical studies on test-driven development (TDD) report different conclusions about its effects on quality and productivity. Very few of those studies are experiments conducted with software professionals in industry. We aim to analyse the effects of TDD on the external quality of the work done and the productivity of developers in an industrial setting. We conducted an experiment with 24 professionals from three different sites of a software organization. We chose a repeated-measures design, and asked subjects to implement TDD and incremental test last development (ITLD) in two simple tasks and a realistic application close to real-life complexity. To analyse our findings, we applied a repeated-measures general linear model procedure and a linear mixed effects procedure. We did not observe a statistical difference between the quality of the work done by subjects in both treatments. We observed that the subjects are more productive when they implement TDD on a simple task compared to ITLD, but the productivity drops significantly when applying TDD to a complex brownfield task. So, the task complexity significantly obscured the effect of TDD. Further evidence is necessary to conclude whether TDD is better or worse than ITLD in terms of external quality and productivity in an industrial setting. We found that experimental factors such as selection of tasks could dominate the findings in TDD studies. 相似文献
24.
V. A. Morgun L. D. Burak A. N. Trofimov 《Journal of Engineering Physics and Thermophysics》1993,64(3):260-265
Results of an experimental investigation of an instrument for measuring high-temperature heat fluxes with a density up to 800 kW/m2 are presented.Notation qinc, Qinc
incident heat flux density
- A, , B, , x
dimensionless parameters
- Ta
adiabatic combustion temperature of fuel
- Hi
instantaneous height of furnace chamber
- H
full height of furnace chamber
- Tf
temperature of gases at the furnace outlet
- Tf
increment in the temperature of gases at the furnace outlet
- af
emissivity of furnace
- Tf
temperature of flame
- 0
Stefan—Boltzmann constant
- T
temperature on the heat pipe body
- Q
supplied power
- Erad
sensitivity of sensor
- D
hourly rate of fuel supplied to the boiler furnace
-
time
Academic Scientific Complex A. V. Luikov Institute of Heat and Mass Transfer of the Academy of Sciences of Belarus, Minsk. I. I. Polzunov Central Boiler and Turbine Institute, St. Petersburg. Scientific and Technical Center Flame-Complex, Ust'-Ilimsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 64, No. 3, pp. 324–329, March, 1993 相似文献
25.
High throughput biological data need to be processed, analyzed, and interpreted to address problems in life sciences. Bioinformatics, computational biology, and systems biology deal with biological problems using computational methods. Clustering is one of the methods used to gain insight into biological processes, particularly at the genomics level. Clearly, clustering can be used in many areas of biological data analysis. However, this paper presents a review of the current clustering algorithms designed especially for analyzing gene expression data. It is also intended to introduce one of the main problems in bioinformatics – clustering gene expression data – to the operations research community. 相似文献
26.
27.
Josef ajka Tom Dostl Kamil Vrba 《International Journal of Circuit Theory and Applications》2004,32(3):133-138
We propose a new current conveyor terminology and explain how these terms are coined. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
28.
With the deployment of native multicast in commercial networks, multicast is getting closer to becoming a ubiquitous service in the Internet. The success of this deployment largely depends on the availability of good management tools and systems. One of the most important management tasks for multicast is to verify the availability of the service to its users. This task is usually referred to as reachability monitoring. Reachability monitoring requires a number of monitoring stations to work together to collect this information in a distributed manner in the interdomain scale. In this paper we present a general architecture for multicast reachability monitoring systems and focus on three critical functions: agent configuration, monitoring, and feedback collection. For each component, we provide a number of alternative approaches to implement the required functionality and discuss their advantages and disadvantages. Then, we focus on the feedback collection component. To a large extent, it determines the complexity and the overhead of a monitoring system. Using simulations, we compare a number of alternative approaches for feedback collection and make suggestions on when to use each. We believe our work provides insight into the issues and considerations in designing and developing multicast reachability monitoring systems. 相似文献
29.
Kamil Sarah M. Gomaa Hosam M. El-Gammal W. Saudi H. A. 《Journal of Materials Science: Materials in Electronics》2021,32(19):24168-24175
Journal of Materials Science: Materials in Electronics - This work is an attempt to estimate the effect of the exchanging of PbO with NiO on the optical and structural parameters for some... 相似文献
30.