全文获取类型
收费全文 | 232篇 |
免费 | 10篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 28篇 |
金属工艺 | 2篇 |
机械仪表 | 4篇 |
建筑科学 | 21篇 |
能源动力 | 9篇 |
轻工业 | 32篇 |
水利工程 | 1篇 |
无线电 | 38篇 |
一般工业技术 | 45篇 |
冶金工业 | 6篇 |
原子能技术 | 1篇 |
自动化技术 | 51篇 |
出版年
2024年 | 1篇 |
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 10篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 11篇 |
2013年 | 17篇 |
2012年 | 6篇 |
2011年 | 25篇 |
2010年 | 4篇 |
2009年 | 22篇 |
2008年 | 16篇 |
2007年 | 23篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1996年 | 3篇 |
1994年 | 5篇 |
1992年 | 2篇 |
1991年 | 2篇 |
排序方式: 共有242条查询结果,搜索用时 15 毫秒
101.
Petteri Packalen Jari Vauhkonen Eveliina Kallio Jussi Peuhkurinen Juho Pitkänen Inka Pippuri 《International journal of remote sensing》2013,34(14):5154-5165
The spatial pattern of trees can be defined as a property of their location in relation to each other. In this study, the spatial pattern was summarized into three categories, regular, random, and clustered, using Ripley's L-function. The study was carried out at 79 sample plots located in a managed forest in Finland. The goal was to study how well the spatial pattern of trees can be predicted by airborne laser scanning (ALS) data. ALS-derived predictions were based upon individual tree detection (ITD), semi-individual tree detection (semi-ITD), and plot-level metrics calculated from the canopy height model, AREA. The kappa value for ITD was almost zero, which indicates no agreement. The semi-ITD and AREA methods performed better, although kappa values were only 0.34 and 0.24, respectively. It appears difficult to detect a particularly clustered spatial pattern. 相似文献
102.
We examine the role of utility models (UM) in patent filing strategies. With an extensive patent family data from European countries, we explore the structures and characteristics of patent families, which include UMs. A simple typology of patent families with UM members is introduced. We document that the geographical scope of most patent families with UM members is purely national, which is in line with the conventional view that the UM mechanism covers technologically and economically marginal inventions. However, the image of a UM as a signal of a minor invention is an oversimplification. Applicants exhibit a mixture of uses for the UM and there exists a subset of UM filings linked to inventions the inventive step of which meets or exceeds the threshold required for patent protection. Some UMs are members of international patent families, indicating that applicants may have some strategic motives to use UMs in international filing. The findings highlight that both types of IPR documents (UMs and patents) should be taken into account when working with data on patent families, analyzing patent filing strategies, and constructing patent-based indicators such as patenting propensities. 相似文献
103.
Olli Hyvärinen Matti Hämäläinen Pertti Lamberg Jussi Liipo 《JOM Journal of the Minerals, Metals and Materials Society》2004,56(8):57-59
HydroCopper? technology comprises a chloride-leaching method for copper sulfide concentrates and copper production up to semi-products. As compared with the commonly used sulfate solutions, brine solutions offer aggressiveness and stability of the copper(I) ion and, consequently, a lower energy consumption in leaching. Copper(II) ions and oxygen are used as oxidants. Iron reports to the leaching residue as oxide and sulfur as elemental sulfur. Gold is dissolved and recovered in the third stage of the counter-current leaching when the redox potential reaches higher levels. 相似文献
104.
Faizan Ul Haq Mikko Englund Kim B. Östman Kari Stadius Marko Kosunen Kimmo Koli Jussi Ryynänen 《International Journal of Circuit Theory and Applications》2019,47(12):1893-1906
In this paper, we investigate the application of the direct ΔΣ receiver (DDSR) concept in a mixer-first architecture. Specifically, we analyze the degrading effects of quantization noise (Qn) upconversion on DDSR sensitivity, which is a major concern in mixer-first DDSR architecture. We demonstrate that with the chosen approach, the mixer-first architecture is suitable for the DDSR despite the potential challenges arising from Qn upconversion. A systematic modeling and understanding of Qn upconversion effects is presented, which lead to simple design guidelines. The results demonstrate that a first-order low-pass Qn filtering is sufficient in most cases for mixer-first DDSR implementations. Based on analytical results, we design a transistor-level mixer-first DDSR by merging the functionality of N-path capacitors both as channel select and Qn filters. Simulations performed in a 28-nm complementary metal-oxideŰsemiconductor (CMOS) process show a mere 1.5-dB degradation from maximum signal-to-noise and distortion ratio (SNDR) for the worst-case scenarios arising from Qn upconversion effects, validating the chosen approach. 相似文献
105.
Tuija Jetsu Ville Heikkinen Anahit Pogosova Timo Jaaskelainen Jussi Parkkinen 《Color research and application》2009,34(5):341-350
Recent break‐throughs in retinal imaging have raised new questions for color vision research, and the existing color vision models should be re‐evaluated. Many color vision models are based on an assumption that there are no differences in the detection phase, neither in the spatial configuration nor in the spectral sensitivities of cells. In this article, we have run experiments with four different color vision models. This evaluation gives us more knowledge about the essential properties of the models. We show how the tested color vision models are able to replicate the behaviour of human color vision by evaluating their performance in Farnsworth‐Munsell 100‐Hue color vision test. Also, the wavelength discrimination power of each model is presented and the properties of color spaces spanned by models are examined using samples from Munsell Book of Color. Our experiments show that there are large differences in the properties of different models. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 341–350, 2009 相似文献
106.
Petteri Paatsila Kari Stadius Jussi Ryyna¨nen 《Analog Integrated Circuits and Signal Processing》2001,26(1):45-52
Three LNAs at 2 GHz frequency range have been implemented in a SiGe Bipolar process targeted for a universal mobile telecommunications system. The LNAs are operating in two gain modes and they include a power-down mode. Both on-wafer and packaged LNAs were measured. Noise figure below 2 dB with IIP3 of 1 dBm and gain exceeding 15 dB has been achieved. LNAs work from a 2.7–5.5 V power supply. A figure of merit method is used to compare this work to other published LNAs. 相似文献
107.
Trends in total organic carbon (TOC) concentrations over the period 1987-2003 were studied in 13 small forest lakes. Recovery from acidification (reduced SO(4) deposition) and long-term changes in runoff as potential drivers for the trends were examined. The results showed that TOC concentrations have increased throughout Finland. Ten of the 13 lakes showed a significant increasing TOC trend (p<0.05), and included both clear water and humic lakes. The largest annual increase in TOC occurred in lakes with the largest average concentrations. The magnitude of the TOC trends were not significantly related to the proportion of peat soils in the catchment but the catchment size was an important predictor. Decreasing SO(4) deposition and improved acid-base status in soil due to the recovery from acidification implied an increased mobilisation of organic acids and TOC. There was little evidence that the long-term increasing trend in TOC concentrations was related to long-term changes in runoff. However, large seasonal and inter-annual fluctuations in runoff did appear to affect TOC concentrations for a number of years. 相似文献
108.
Ashok Kumar Veerasamy Daryl D'Souza Rolf Lindn Mikko‐Jussi Laakso 《Journal of Computer Assisted Learning》2019,35(2):246-255
Past research has shown that student problem‐solving skills may be used to determine student final exam performance. This study reports on the relationship between student perceived problem‐solving skills 1 1 Henceforth, for brevity, we drop the word “perceived” in “student perceived problem‐solving skills” and use either “student perceived problem solving” or simply “student PSS.”
and academic performance in introductory programming, in formative and summative programming assessment tasks. We found that the more effective problem solvers achieved better final exam scores. There was no significant difference in formative assessment performances between effective and poor problem solvers. It is also possible to categorize students on the basis of problem‐solving skills, in order to exploit opportunities to improve learning around constructivist learning theory. Finally, our study identified transferability skills and the study may be extended to identify the impact of problem solving transfer skills on student problem solving for programming. 相似文献
and academic performance in introductory programming, in formative and summative programming assessment tasks. We found that the more effective problem solvers achieved better final exam scores. There was no significant difference in formative assessment performances between effective and poor problem solvers. It is also possible to categorize students on the basis of problem‐solving skills, in order to exploit opportunities to improve learning around constructivist learning theory. Finally, our study identified transferability skills and the study may be extended to identify the impact of problem solving transfer skills on student problem solving for programming. 相似文献
109.
110.
Efficient Management of Fines in the Stock Flow prior to Headbox in Paper, Board, and Tissue Production 下载免费PDF全文
Jouni Matul Jussi Matul Jukka Nokelainen Tommi Niskanen Lasse Kauppinen Eemeli Siitonen 《造纸与生物质材料》2022,(1):45-54
Fines represent a significant volume of biobased wood material and filler, which is of significant importance to sheet quality. New imaging technology reveals the true nature of the behavior of fines in the retention process. This study illustrates new chemical mixing systems, novel and efficient flash mixing methods, and active measurement and automation systems pertaining to efficient management of fines in the stock flow prior to headbox in paper, board, and tissue production, which can reduce additive, fresh water, energy consumption, and the carbon footprint of production to improve sustainability and provide novel opportunities for fines and filler management. 相似文献