首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   169篇
  免费   8篇
电工技术   1篇
化学工业   25篇
金属工艺   2篇
建筑科学   5篇
轻工业   13篇
水利工程   2篇
石油天然气   3篇
无线电   30篇
一般工业技术   29篇
冶金工业   42篇
自动化技术   25篇
  2023年   2篇
  2022年   3篇
  2021年   7篇
  2020年   1篇
  2019年   5篇
  2018年   5篇
  2017年   4篇
  2016年   1篇
  2015年   4篇
  2014年   1篇
  2013年   4篇
  2012年   5篇
  2011年   14篇
  2010年   5篇
  2009年   5篇
  2008年   3篇
  2007年   11篇
  2006年   1篇
  2005年   8篇
  2004年   5篇
  2003年   9篇
  2002年   4篇
  2001年   4篇
  2000年   4篇
  1999年   3篇
  1998年   1篇
  1997年   4篇
  1996年   5篇
  1995年   2篇
  1994年   8篇
  1993年   7篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1989年   4篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1984年   2篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1977年   3篇
  1975年   2篇
  1973年   3篇
  1962年   1篇
排序方式: 共有177条查询结果,搜索用时 218 毫秒
1.
2.
Using vector quantization for image processing   总被引:1,自引:0,他引:1  
A review is presented of vector quantization, the mapping of pixel intensity vectors into binary vectors indexing a limited number of possible reproductions, which is a popular image compression algorithm. Compression has traditionally been done with little regard for image processing operations that may precede or follow the compression step. Recent work has used vector quantization both to simplify image processing tasks, such as enhancement classification, halftoning, and edge detection, and to reduce the computational complexity by performing the tasks simultaneously with the compression. The fundamental ideas of vector quantization are explained, and vector quantization algorithms that perform image processing are surveyed  相似文献   
3.
The recently reported hole-patterned YBa2Cu3O y (Y123) bulks with improved superconducting properties are highly interesting from material quality and application variety points of view. It is well known that the core of plain bulk superconductors needs to be fully oxygenated and some defects like cracks, pores, and voids must be suppressed in order that the material can trap a high magnetic field or carry a high current density. To minimize the above defects, we have used a combination of standard superconducting ceramic processing and an infiltration technique to prepare regularly perforated YBa2Cu3O y (Y123) bulk superconductors. This process leads to negligible shrinkage upon annealing and a uniform distribution of Y211 inclusions. Texture was evidenced by neutron pole figure measurements. Flux mapping was used to verify the superconducting homogeneity of the samples and to investigate the field-trapping ability. In addition, the textured drilled samples were reinforced using resin or metal impregnation and the influence of the different processing steps on the hardness of the materials has been investigated.  相似文献   
4.
5.
6.
Enzymatically treated cellulose was dissolved in a NaOH/ZnO solvent system and mixed together with poly(ethylene‐co‐acrylic acid) (PE‐co‐AA) or poly(acrylamide‐co‐acrylic acid) (PAA‐co‐AA) polymers, in order to improve the properties of dissolved cellulose and to prepare homogeneous cellulose‐based blends for films and coatings. The solution stage properties of the blends were evaluated by rheological methods and the precipitated dry blends were characterized by dynamic mechanical analysis, differential scanning calorimetry, and scanning electron microscopy. Paperboard coating tests done at laboratory scale showed dissolved cellulose/acrylic acid copolymer‐based blends function well as coating materials. All of the tested blends showed a good resistance against grease in the coating trials, having grease resistance from 60 to 69 days despite a very thin (~2 µm) coating layer. In addition, cellulose/PE‐co‐AA coating showed improved water vapor and oxygen barrier properties when compared with neat dissolved cellulose‐coated paperboard. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40286.  相似文献   
7.
Gene regulatory networks model regulation in living organisms. Fuzzy logic can effectively model gene regulation and interaction to accurately reflect the underlying biology. A new multiscale fuzzy clustering method allows genes to interact between regulatory pathways and across different conditions at different levels of detail. Fuzzy cluster centers can be used to quickly discover causal relationships between groups of coregulated genes. Fuzzy measures weight expert knowledge and help quantify uncertainty about the functions of genes using annotations and the gene ontology database to confirm some of the interactions. The method is illustrated using gene expression data from an experiment on carbohydrate metabolism in the model plant Arabidopsis thaliana. Key gene regulatory relationships were evaluated using information from the gene ontology database. A new regulatory relationship concerning trehalose regulation of carbohydrate metabolism was also discovered in the extracted network.  相似文献   
8.
BACKGROUND: Some European pear varieties treated with 1‐methylcyclopropene (1‐MCP) often remain ‘evergreen’, meaning that their ripening process is blocked and does not resume after removal from cold storage. In this work this was confirmed also to be the case in ‘Conference’ pears. To reverse the blockage of ripening 1‐MCP treatments combined with external exogenous ethylene were tested. RESULTS: 1‐MCP treatment of ‘Conference’ pears is very effective in delaying ripening and, more specifically, softening. The same 1‐MCP concentration in different experimental years caused a different response. The higher dose of 1‐MCP (600 nL L?1) always resulted in irreversible blockage of ripening, whereas the behaviour of fruit receiving a lower dose (300 nL L?1) depended on the year, and this did not depend on maturity at harvest or on storage conditions. Simultaneous exposure to 1‐MCP and exogenous ethylene significantly affected fruit ripening, allowing significant softening to occur but at a lower rate compared with control fruit. CONCLUSION: The application of exogenous ethylene and 1‐MCP simultaneously after harvest permitted restoration of the ripening process after storage in ‘Conference’ pears, extending the possibility of marketing and consumption. Copyright © 2011 Society of Chemical Industry  相似文献   
9.
Previous work suggested the association between intentionality and the reported time of action was exclusive, with intentionality as the primary facilitator to the mental time compression between the reported time of action and its effect (Haggard, Clark, & Kalogeras, 2002). In three experiments, we examined whether mental time compression could also be observed in an unintended action. Participants performed an externally cued key press task that elicited one of two possible tones. The reported time of action shifted closer to the tone when the tone was used to indicate the winner of a race (Exp.2) compared to when the tone was meaningless and did not indicate winning (Exp.1). This suggests that reported time of an unintended action could shift toward the effect in some contexts. Furthermore, the results from Exp.2 and Exp.3 (tones were substituted with verbal feedback) showed that a presumed winning action was judged to occur earlier whereas a presumed losing action was judged to be later. These findings therefore support the view that the reported time of action is reconstructed from known temporal information rather than determined by intentionality. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
10.
The functional recovery of 47 right-brain-damaged stroke patients was studied over a 2-year period. The researchers hypothesized that sustained attention capacity should predict the degree of motor and functional recovery over this period because of a proposed privileged role of sustained attention in learning-based recovery of function. As predicted, significant correlations were found between sustained attention capacity at 2 months and functional status (including the Barthel Index) at 2 years. This relationship was shown to exist independently of 2-month functional status. Furthermore, compared with a left-brain-damaged group of cerebrovascular accident (CVA) patients, the right-brain CVA group did not recover functional ability as well over the 2-year period. This increasing difference in functional status over a 2-year period was mirrored by an emerging difference in sustained attention capacity, in favor of the left-brain CVA group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号