全文获取类型
收费全文 | 728篇 |
免费 | 10篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 17篇 |
综合类 | 6篇 |
化学工业 | 127篇 |
金属工艺 | 22篇 |
机械仪表 | 29篇 |
建筑科学 | 17篇 |
矿业工程 | 1篇 |
能源动力 | 46篇 |
轻工业 | 29篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 163篇 |
一般工业技术 | 137篇 |
冶金工业 | 56篇 |
原子能技术 | 3篇 |
自动化技术 | 87篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 11篇 |
2021年 | 9篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 17篇 |
2013年 | 60篇 |
2012年 | 25篇 |
2011年 | 28篇 |
2010年 | 29篇 |
2009年 | 34篇 |
2008年 | 38篇 |
2007年 | 27篇 |
2006年 | 22篇 |
2005年 | 20篇 |
2004年 | 26篇 |
2003年 | 33篇 |
2002年 | 22篇 |
2001年 | 30篇 |
2000年 | 16篇 |
1999年 | 25篇 |
1998年 | 27篇 |
1997年 | 21篇 |
1996年 | 29篇 |
1995年 | 14篇 |
1994年 | 16篇 |
1993年 | 26篇 |
1992年 | 10篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1989年 | 13篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有745条查询结果,搜索用时 15 毫秒
21.
Mobile data communications have evolved as the number of third generation (3G) subscribers has increased. The evolution has triggered an increase in the use of mobile devices, such as mobile phones, to conduct mobile commerce and mobile shopping on the mobile web. There are fewer products to browse on the mobile web; hence, one‐to‐one marketing with product recommendations is important. Typical collaborative filtering (CF) recommendation systems make recommendations to potential customers based on the purchase behaviour of customers with similar preferences. However, this method may suffer from the so‐called sparsity problem, which means there may not be sufficient similar users because the user‐item rating matrix is sparse. In mobile shopping environments, the features of users' mobile phones provide different functionalities for using mobile services; thus, the features may be used to identify users with similar purchase behaviour. In this paper, we propose a mobile phone feature (MPF)‐based hybrid method to resolve the sparsity issue of the typical CF method in mobile environments. We use the features of mobile phones to identify users' characteristics and then cluster users into groups with similar interests. The hybrid method combines the MPF‐based method and a preference‐based method that uses association rule mining to extract recommendation rules from user groups and make recommendations. Our experiment results show that the proposed hybrid method performs better than other recommendation methods. 相似文献
22.
Chao-Che Hsu James J.H. Liou Yen-Ching Chuang 《Expert systems with applications》2013,40(6):2297-2304
Globalization has inevitably forced firms to pursue outsourcing as a strategy to reduce operating costs and improve their competitiveness in the global marketplace. However, a successful outsourcing activity depends on the selection of the appropriate provider. Unlike previous multiple criteria decision-making (MCDM) methods that assume the criteria are independent, we propose a novel hybrid model, combining a Decision Making Trial and Evaluation Laboratory (DEMATEL) and Analytical Network Process (ANP) method called DANP, which addresses the dependent relationships between the various criteria to better reflect the real-world situation. At the same time, instead of ranking the alternatives, we apply a modified grey relation method to select and improve the criterion-gaps to the aspiration levels. To demonstrate the usefulness and effectiveness of the proposed model, we use data from a Taiwanese company. 相似文献
23.
Self‐Crack‐Filled Graphene Films by Metallic Nanoparticles for High‐Performance Graphene Heterojunction Solar Cells 下载免费PDF全文
24.
Yi‐Bing Lin Ren‐Huang Liou Chun‐Ting Chang 《Wireless Communications and Mobile Computing》2015,15(4):629-638
In long‐term evolution, the service area is partitioned into several tracking areas (TAs), which comprise one or more cells (the radio coverages of base stations). The TAs are grouped into TA list (TAL). When an incoming call arrives, the network attempts to connect to the user equipment (UE) by paging the cells in the UE's TAL, which may incur large paging traffic that significantly consumes the limited radio resources. To resolve this issue, this paper proposes a dynamic paging scheme that determines the paging sequence of cells in real time according to the UE movement and call behavior. We compare the performance of the dynamic paging with that of the previously proposed Cell‐TA‐TAL (CTT) paging. Our study indicates that the dynamic paging outperforms the CTT paging when movement pattern is regular and the UE moves frequently. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
25.
26.
W. Liou 《Journal of microscopy》1990,157(2):239-245
A technique is given for the preparation of a sheet of epithelial cells from the capsule of the crystalline lens. A new method is described for fixation and staining with fluorescent phalloidin or actin antibody in order to localize the actin cytoskeleton in this tissue. Optical section of the preparation resolves such actin features as apical polygonal arrays, sequestered actin bundles, perinuclear actin aggregates, observed here for the first time, and filamentous networks in the basal region of the cell. This method is superior to previous ones in its ability to preserve actin-abundant sectors distinctively. 相似文献
27.
28.
Manzella V. Chrien R. E. Gill R. L. Liou H. I. Stelts M. L. 《IEEE transactions on nuclear science》1981,28(5):3761-3763
The nuclear physics program at the Brookhaven National Laboratory High Flux Beam Reactor (HFBR) employs a pair of PDP-11 computers for the dual functions of data acquisition and analysis. The data acquisition is accomplished through CAMAC and features a microprogrammed branch driver to accommodate various experimental inputs. The acquisition computer performs the functions of multi-channel analyzers, multiscaling and time-sequenced multichannel analyzers and gamma-ray coincidence analyzers. The data analysis computer is available for rapid processing of data tapes written by the acquisition computer. The ability to accommodate many users is facilitated by separating the data acquisition and analysis functions, and allowing each user to tailor the analysis to the specific requirements of his own experiment. The system is to be upgraded soon by the introduction of a dual port disk to allow a data base to be available to each computer. 相似文献
29.
滚齿加工齿轮误差的矢量法分析 总被引:1,自引:1,他引:1
从共轭原理角度出发,采用矢量法分析了运动偏心下滚齿加工轮齿的本质,阐明了有运动偏心的情况下,滚切出的齿形是有误差的渐开线齿形。 相似文献
30.
Shibo Li Liou Xiao Guiming Song Xiaomin Wu Wim G. Sloof Sybrand van der Zwaag 《Journal of the American Ceramic Society》2013,96(3):892-899
This work reports the oxidation and crack healing behavior of a fine‐grained (~2 μm) Cr2AlC MAX phase ceramic. The oxidation behavior was investigated in the temperature range 900°C–1200°C for times up to 100 h. The material showed a good oxidation resistance, owing to the formation of a dense and thin α‐Al2O3 layer. The microstructure, composition and thickness of the oxide scale were characterized. Its oxidative crack healing behavior as a function of temperature, healing time, and initial crack size was studied systematically. The material showed excellent healing behavior. The main crack healing mechanism is the filling of the crack by oxides well adhering to the crack faces. The crack geometry before and after healing was characterized by X‐ray tomography. Three‐point bend tests showed the dependence of strength recovery at 1100°C as a function of initial crack length and healing time. 相似文献