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2.
The use of light gauge steel framing is increasing rapidly. New methods for joining frames are being sought. One of the most promising methods is clinching. Clinching has been used for almost 20 years. There has been much research into the method, the tools, suitable materials and applications. Few articles have been published concerning clinching of high strength structural steels, which are currently the most relevant materials for house construction.This study included 11 different clinching methods. In total, 469 test pieces were produced. Despite the high strength of the materials, all the clinching methods that were examined could be used satisfactorily. The most significant result was that a round tool is appropriate for all the materials tested. In fact, in comparison with results obtained using other types of tool, when the methods were ranked by maximum shear load capacity, the round design appeared in the top three classes seven times out of nine. 相似文献
3.
Wood inspection with non-supervised clustering 总被引:9,自引:0,他引:9
Abstract. The appearance of sawn timber has huge natural variations that the human inspector easily compensates for mentally when determining
the types of defects and the grade of each board. However, for automatic wood inspection systems these variations are a major
source for complication. This makes it difficult to use textbook methodologies for visual inspection. These methodologies
generally aim at systems that are trained in a supervised manner with samples of defects and good material, but selecting
and labeling the samples is an error-prone process that limits the accuracy that can be achieved. We present a non-supervised
clustering-based approach for detecting and recognizing defects in lumber boards. A key idea is to employ a self-organizing
map (SOM) for discriminating between sound wood and defects. Human involvement needed for training is minimal. The approach
has been tested with color images of lumber boards, and the achieved false detection and error escape rates are low. The approach
also provides a self-intuitive visual user interface.
Received: 16 December 2000 / Accepted: 8 December 2001
Correspondence to: O. Silvén 相似文献
4.
Marja Riekkola-Vanhanen Ph.Lic. Seppo Heimala D.Sc. Carita A. Sivelä M.Sc. Felipe Viguera M.Sc. Irma Varjola M.Sc. Seppo I. Niemelä Ph.D. Olli H. Tuovinen Ph.D. 《JOM Journal of the Minerals, Metals and Materials Society》1993,45(12):51-53
The oxidation of an auriferous pyrite ore sample was evaluated in biological leaching experiments for subsequent gold recovery via cyanidation. In batch cultures, organisms derived from the mine site oxidized pyrite and ferrous iron at pH values as low as pH 0.6. The recovery of gold was variable in shake flask experiments. In stirred tank bioreactor leaching, gold recovery was proportional to the extent of iron dissolution by bioleaching. The leaching of arsenic from the sample was also directly proportional to iron dissolution. 相似文献
5.
Olli Varis 《国际水》2013,38(4):624-637
Abstract The Nile brings virtually no water to the sea. The mighty basin with 1/10 of Africa's land area and 1/3 of its population, has only 1/16 of its water. The riparian countries use practically all of the Nile's water and they face increasing challenges in terms of environmental degradation, food security, and socioeconomic development. The geopolitical situation blocks the integrated development of water resources in the basin scale, yet the political environment may be improving. The Nile basin is among the most critical regions of the world in terms of water resources development. In this article, the trends of the major driving forces within the basin countries—population, urbanization, climate, agriculture, economy, human resources, and governance—are scrutinized from the viewpoint of their impacts on water resources and their management. A comparison is made to four other critical macroregions: China, South Asia, Southeast Asia, and West Africa. 相似文献
6.
针对长江流域目前面临的诸多挑战,结合对第四届长江论坛关注点的回顾,总结了以长江流域发展为重点的研究成果,分析了沿江各省(区、市)的关注点与需求以及中国水资源政策与国际通用政策之间的异同,从而得出中国水资源政策应趋向国际通用政策及欧盟《水框架指令》的结论。 相似文献
7.
Kaisa Grönman Risto Soukka Terhen Järvi‐Kääriäinen Juha‐Matti Katajajuuri Mika Kuisma Heta‐Kaisa Koivupuro Margareetta Ollila Marja Pitkänen Olli Miettinen Frans Silvenius Rabbe Thun Helena Wessman Lassi Linnanen 《Packaging Technology and Science》2013,26(4):187-200
The environmental impacts of packages have been found to be relatively small compared with the food items they contain. Furthermore, from the environmental and operational point of view, the most significant task of the package is to protect the product, which is important to acknowledge in the packaging design process. This study introduces a guiding framework for designing sustainable food packaging. In this approach, the entire life cycle of the product–package combination is taken into consideration. The emphasis is on the prevention of food losses in packaging design as a major environmental criterion. Consideration of the properties of both the package and the product itself when designing the final package will lead to a better end result with smaller product losses and environmental impacts. By using different assessment methods in the different stages of the packaging design, the sustainability of the package can be enhanced. The decision making of the packaging designer is facilitated with methods that are introduced step by step and in a certain order that will also allow for corrective measures through back‐loops in the design process. The purpose is to integrate sustainability aspects at all stages firmly into the design process. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
8.
采用三步分离法,其中第一步用水,第二步用乙酸铵,第三步用盐酸,提取纸浆发电厂生物质飞灰和底灰的组分,以评估这些残渣的浸出行为。除了Mo、S、Na以及那些浓度低于检测范围的元素外,在这两种灰份中,对于其他元素这三种浸出剂的浸出能力从弱到强的顺序为:水、乙酸铵和盐酸。采用三步分离法处理的废渣中元素浓度比前期用BCR连续提取法得到的低。 相似文献
9.
10.
For determining distances (fetch lengths) from points to polygons in a two‐dimensional Euclidean plane, cell‐based algorithms provide a simple and effective solution. They divide the input area into a grid of cells that cover the area. The objects are stored into the appropriate cells, and the resulting structure is used for solving the problem. When the input objects are distributed unevenly or the cell size is small, most of the cells may be empty. The representation is then called sparse. In the method proposed in this work, each cell contains information about its distance to the nonempty cells. It is then possible to skip over several empty cells at a time without memory accesses. A cell‐based fetch length algorithm is implemented on a graphics processing unit (GPU). Because control flow divergence reduces its performance, several methods to reduce the divergence are studied. While many of the explicit attempts turn out to be unsuccessful, sorting of the input data and sparse traversal are observed to greatly improve performance: compared with the initial GPU implementation, up to 45‐fold speedup is reached. The speed improvement is greatest when the map is very sparse and the points are given in a random order. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献