全文获取类型
收费全文 | 548篇 |
免费 | 26篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 57篇 |
综合类 | 3篇 |
化学工业 | 186篇 |
金属工艺 | 7篇 |
机械仪表 | 12篇 |
建筑科学 | 28篇 |
能源动力 | 20篇 |
轻工业 | 56篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 30篇 |
一般工业技术 | 90篇 |
冶金工业 | 12篇 |
原子能技术 | 9篇 |
自动化技术 | 62篇 |
出版年
2023年 | 5篇 |
2022年 | 11篇 |
2021年 | 17篇 |
2020年 | 3篇 |
2019年 | 9篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 18篇 |
2014年 | 22篇 |
2013年 | 43篇 |
2012年 | 18篇 |
2011年 | 37篇 |
2010年 | 32篇 |
2009年 | 30篇 |
2008年 | 30篇 |
2007年 | 28篇 |
2006年 | 18篇 |
2005年 | 25篇 |
2004年 | 25篇 |
2003年 | 20篇 |
2002年 | 15篇 |
2001年 | 5篇 |
2000年 | 12篇 |
1999年 | 10篇 |
1998年 | 10篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 10篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1975年 | 4篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1968年 | 2篇 |
排序方式: 共有576条查询结果,搜索用时 15 毫秒
571.
This paper describes a newly developed software program with its simulation results for a machining shop of FMS (Flexible Manufacturing Systems), which has features of discreteness and concurrency. To overcome these difficulties, we adopted an event-driven structure for a program by employing a Petri Net graph to depict all operational states and transitions. The simulation program outputs necessary and sufficient results of this discrete and concurrent system in a short execution time by a popular computer of a sequential machine. 相似文献
572.
José L. Balcázar Yang Dai Junichi Tanaka Osamu Watanabe 《Theory of Computing Systems》2008,42(4):568-595
Support Vector Machines are a family of algorithms for the analysis of data based on convex Quadratic Programming. We derive
randomized algorithms for training SVMs, based on a variation of Random Sampling Techniques; these have been successfully
used for similar problems. We formally prove an upper bound on the expected running time which is quasilinear with respect
to the number of data points and polynomial with respect to the other parameters, i.e., the number of attributes and the inverse
of a chosen soft margin parameter. [This is the combined journal version of the conference papers (Balcázar, J.L. et al. in
Proceedings of 12th International Conference on Algorithmic Learning Theory (ALT’01), pp. 119–134, [2001]; Balcázar, J.L. et al. in Proceedings of First IEEE International Conference on Data Mining (ICDM’01), pp. 43–50, [2001]; and Balcázar, J.L. et al. in Proceedings of SIAM Workshop in Discrete Mathematics and Data Mining, pp. 19–29, [2002]).]
The first and the fourth authors started this research while visiting the Centre de Recerca Matemàtica of the Institute of
Catalan Studies in Barcelona.
The first author was supported by IST Programme of the EU under contract number IST-1999-14186 (ALCOM-FT), Spanish Government
TIC2004-07925-C03-02, and CIRIT 2001SGR-00252.
The second author conducted this research while she was with Department of Mathematical and Computing Sciences, Tokyo Institue
of Technology, and was supported by a Grant-in-Aid (C-13650444) from Japanese Goverment.
The fourth author was supported in part by a Grant-in-Aid for Scientific Research on Priority Areas “Discovery Science” 1998–2000
from Japanese Goverment. 相似文献
573.
Yuki Otsuka Isao Yamamoto Motoyuki Iijima Junichi Tatami 《International Journal of Applied Ceramic Technology》2023,20(2):708-717
Controlling the crystal orientation of hydroxyapatite, an inorganic material that is a major component of human hard tissues is important to fabricate better artificial bones and artificial tooth roots. To obtain highly oriented hydroxyapatite ceramics under a strong magnetic field, a good dispersion of the raw materials in the slurry must be obtained. This study investigates the effect of wet-jet milling of a slurry on the orientation of hydroxyapatite ceramics fabricated using a strong magnetic field. Although the prolonged ball milling with ZrO2 balls of the raw powder fractures the primary particles of hydroxyapatite, wet-jet milling is used to successfully pulverize agglomerated hydroxyapatite raw powder without changing the morphology of the primary particles. Evidently, ceramics with a highly oriented c-axis of hydroxyapatite are obtained by molding the wet-jet milled slurry in a strong rotating magnetic field. They exhibit anisotropy in fracture toughness, and the fracture toughness calculated from the crack length perpendicular to the rotating axis is higher than that calculated from the crack length parallel to it. Furthermore, these values are higher than those of randomly oriented hydroxyapatite ceramics, which may be owing to the crystal orientation dependence of the fracture toughness of the hydroxyapatite grains and grain boundaries. 相似文献
574.
This laboratory-scale study attempted performance improvement and decolourization in the high-solid thermophilic anaerobic digestion of thermally pretreated sewage sludge, as it tends to be disturbed by ammonia inhibition and colour generation. Sewage sludge was adjusted to 7%–8% total solids (TS), and pretreated at 150°C for 1 h. The digesters were operated at 55°C and 20 days hydraulic retention time. An addition of powdered activated carbon (approximately 2% of the feed TS) significantly contributed to the removal of propionate and reduced the colour in digested sludge by about 27%. Microbial analysis detected less abundance of bacterial Synergistia and archaeal Methanosarcina and implied more hydrogenotrophic methanogenesis with the activated carbon addition. Conditioning with ferric chloride for dewatering digested sludge mitigated the colour of dewatered liquor by about 67%. Therefore, these methods were demonstrated to be effective and partly overcome the above-mentioned problems. 相似文献
575.
Takuma Takahashi Fumika Sakamoto Junichi Tatami Motoyuki Iijima 《International Journal of Applied Ceramic Technology》2022,19(2):1171-1179
In situ observation of sintering of ceramics is important to understand the sintering behavior, including the development of internal structures, and to fabricate ceramics with superior properties. However, there has been no studies thus far on high-speed in situ observation of the internal structure of green and sintered bodies at high temperatures with micrometer-scale resolution. Here, we applied swept-source optical coherence tomography (OCT) to observe the evolution of the internal structure in Al2O3 green bodies during sintering. In situ OCT observations revealed that internal structure changes during sintering, such as the development of density distribution and growth of coarser pores. We could also obtain the sintering shrinkage ratio and relative density from the OCT images. The OCT observation of the internal structure during sintering of green bodies with added or stacked granules of different primary particle sizes confirmed that inhomogeneous regions developed as the densification progressed at high temperatures. These results indicate that in situ observation of the sintering behavior of ceramic green bodies using swept-source OCT is a novel technique that facilitates real-time observation of the evolution of the internal structure during sintering. 相似文献
576.
Mami Tanabe Junichi Tatami Motoyuki Iijima Tsukaho Yahagi Takuma Takahashi Hiromi Nakano Tatsuki Ohji 《Journal of the American Ceramic Society》2023,106(9):5431-5439
In this study, the yield stress and fracture strength of -Si3N4 single crystals were directly measured by bending tests of microcantilever beam specimens that were prepared by a focused ion beam method. The -Si3N4 single crystals were plastically deformed at room temperature under high bending stress, and the yield stress depended on the crystal orientation. Transmission electron microscopy observation of the specimens after bending tests indicates that the plastic deformation resulted from dislocations in the primary slip system <0001>, and the critical resolved shear stress of this slip system determined from the yield stress was 1.34 GPa. The fracture strength of -Si3N4 single crystals ranged approximately up to 20 GPa, depending on the crystal orientation as with the yield stress. The fracture behavior of -Si3N4 single crystals was discussed in terms of the accumulation of dislocations. 相似文献