全文获取类型
收费全文 | 3224篇 |
免费 | 204篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 40篇 |
化学工业 | 815篇 |
金属工艺 | 40篇 |
机械仪表 | 84篇 |
建筑科学 | 128篇 |
矿业工程 | 5篇 |
能源动力 | 114篇 |
轻工业 | 568篇 |
水利工程 | 29篇 |
石油天然气 | 19篇 |
无线电 | 204篇 |
一般工业技术 | 473篇 |
冶金工业 | 116篇 |
原子能技术 | 13篇 |
自动化技术 | 788篇 |
出版年
2024年 | 7篇 |
2023年 | 39篇 |
2022年 | 127篇 |
2021年 | 143篇 |
2020年 | 115篇 |
2019年 | 132篇 |
2018年 | 121篇 |
2017年 | 109篇 |
2016年 | 142篇 |
2015年 | 112篇 |
2014年 | 147篇 |
2013年 | 286篇 |
2012年 | 236篇 |
2011年 | 264篇 |
2010年 | 210篇 |
2009年 | 192篇 |
2008年 | 179篇 |
2007年 | 152篇 |
2006年 | 124篇 |
2005年 | 96篇 |
2004年 | 77篇 |
2003年 | 64篇 |
2002年 | 69篇 |
2001年 | 35篇 |
2000年 | 33篇 |
1999年 | 27篇 |
1998年 | 29篇 |
1997年 | 20篇 |
1996年 | 21篇 |
1995年 | 20篇 |
1994年 | 12篇 |
1993年 | 19篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1967年 | 1篇 |
1945年 | 1篇 |
排序方式: 共有3436条查询结果,搜索用时 31 毫秒
111.
This paper describes an application framework supporting collaborative handheld decision-making (CHDM). The main characteristics of the framework are: (1) extensive usage of visual elements and gestures; and (2) independence from specific decision-making methods, processes and tasks. The research departed from the analysis and systematisation of several CHDM scenarios, highlighting repeatable behaviour across multiple decision-making contexts. From these scenarios, we distilled a coherent set of common functional requirements organised in three main categories: process, macro- and micro-functionality. The proposed framework has been validated at length through the development of several CHDM tools. Six different tools are described in the paper. The main contribution of this work is a common foundation for developing CHDM tools. 相似文献
112.
Antonio J. Suárez Fábrega José Manuel Bravo Caro Pedro J. Abad Herrera Rafael M. Gasca 《International Journal of Adaptive Control and Signal Processing》2014,28(12):1299-1324
In this paper, a new data‐driven fault‐detection method is proposed. This method is based on a new nonparametric system identification approach, which constitutes the principal contribution to this work. The fault‐detection method is a parametric model‐free approach that can be applied to nonlinear systems that work at various operating points. Not only can the fault‐detection process be applied to the steady state of each operating point, but it can also be applied to the transient state resulting from a change in the operating point. In order to detect faults, the proposed method uses an interval predictor based on bounded‐error techniques. The utilization of techniques based on bounded error enables system uncertainties to be included in an explicit way. This in turn leads to the possibility of obtaining interval predictions of the behaviour of the system, which include information on the reliability of the prediction itself. In order to show the effectiveness of the fault‐detection method, two examples are presented: in the form of a simulated process (counter‐flow shell‐and‐tube heat‐exchanger system) and an example of a real application (two‐tanks system). A comparison with two fault‐detection methods has also been included. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
113.
114.
Roberto C. Dante Francisco M. Sánchez-Arévalo Pedro Chamorro-Posada José Vázquez-Cabo Lazaro Huerta Luis Lartundo-Rojas 《Fullerenes, Nanotubes and Carbon Nanostructures》2016,24(3):171-180
Polymeric carbon nitride doped with copper through a solid-state reaction was characterized by several techniques, among them are UV-visible spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, etc. The material is a semiconductor with a wide band gap of 2.74 eV. Sites of both Cu(I) and Cu(II) were detected, apparently only coordinated by the polymer. The material comprises crumpled nanosheets, and is substantially an amorphous layered material with a prevalent 2D structure with low inter-planar interactions, as shown by X-ray diffractometry and TeraHertz spectroscopy. Photo-oxidation of benzyl alcohol was used to probe the active sites of the material, comparing them with the non-doped material. The higher activity and selectivity toward salicylic alcohol of the non-doped material can be due to both a more localized electron transfer and a longer lifetime of the hole–electron pair. Cu-CN favored the oxidation of hydroxymethyl group. Therefore, the presence of copper can favor different reaction pathways with respect to the non-doped material. 相似文献
115.
116.
117.
A theoretical analysis is reported in the present work to quantify the increase of radiative emission due to turbulence for hydrogen and hydrogen-enriched methane diffusion flames burning in air. The instantaneous thermochemical state of the reactive mixture is described by a flamelet model along with a detailed chemical mechanism. The shape of the probability density function (pdf) of mixture fraction is assumed. The results show that turbulent fluctuations generally contribute to reduce the Planck mean absorption coefficient of the medium, in contrast with the blackbody emissive power, which is significantly increased by turbulence. If the turbulence level is relatively small, the influence of turbulence on the absorption coefficient is marginal. Otherwise, fluctuations of the absorption coefficient of the medium should be taken into account. The scalar dissipation rate and the fraction of radiative heat loss have a much lower importance than the turbulence intensity on the mean radiative emission. 相似文献
118.
119.
Manuel Melgosa Guihua Cui Claudio Oleari Pedro J. Pardo Min Huang Changjun Li Ming Ronnier Luo 《Coloration Technology》2017,133(4):273-282
We have used 13 experimental datasets (7420 colour pairs) to study the performance of the weighting function for lightness proposed by the CIEDE2000 colour-difference formula, because it has been suggested that this function can be improved by using the weighting function for lightness SL = 1 adopted by the CIE94 colour-difference formula. Using the standardised residual sum of squares (STRESS) index, it was found that: (i) replacing the SL in CIEDE2000 with SL = 1 improved the results for 7/13 datasets considered, but the improvement was statistically significant only for 1/13 datasets; (ii) a Whittle-type lightness-difference formula can be used to replace the term ∆L*/SL in CIEDE2000, which led to a new colour-difference formula with no statistically significant difference with respect to CIEDE2000 for any of the 13 experimental datasets. A modification of the CIEDE2000 formula using a Whittle-type lightness formula is proposed. 相似文献
120.
Santiago Iglesias-Pradas Pedro Fernández-Cardador 《Information Systems Management》2017,34(3):220-237
ABSTRACTThis study investigates employees’ acceptance of corporate Web 2.0 applications for collaboration and knowledge sharing. Results show that altruism, managerial support, and perceived usefulness are good predictors of the intention to use corporate blogs as tools for collaboration and knowledge sharing. The study further explores differences between employees from companies with low and high adoption rates, and uses prediction-oriented segmentation to unveil two different paths to adoption of Web 2.0 collaborative tools in companies. 相似文献