全文获取类型
收费全文 | 4941篇 |
免费 | 543篇 |
国内免费 | 499篇 |
专业分类
电工技术 | 164篇 |
综合类 | 341篇 |
化学工业 | 198篇 |
金属工艺 | 170篇 |
机械仪表 | 250篇 |
建筑科学 | 215篇 |
矿业工程 | 87篇 |
能源动力 | 55篇 |
轻工业 | 120篇 |
水利工程 | 10篇 |
石油天然气 | 61篇 |
武器工业 | 17篇 |
无线电 | 619篇 |
一般工业技术 | 264篇 |
冶金工业 | 30篇 |
原子能技术 | 17篇 |
自动化技术 | 3365篇 |
出版年
2023年 | 49篇 |
2022年 | 64篇 |
2021年 | 90篇 |
2020年 | 116篇 |
2019年 | 108篇 |
2018年 | 100篇 |
2017年 | 139篇 |
2016年 | 151篇 |
2015年 | 210篇 |
2014年 | 280篇 |
2013年 | 268篇 |
2012年 | 323篇 |
2011年 | 395篇 |
2010年 | 294篇 |
2009年 | 302篇 |
2008年 | 337篇 |
2007年 | 391篇 |
2006年 | 345篇 |
2005年 | 307篇 |
2004年 | 237篇 |
2003年 | 224篇 |
2002年 | 175篇 |
2001年 | 114篇 |
2000年 | 111篇 |
1999年 | 102篇 |
1998年 | 102篇 |
1997年 | 73篇 |
1996年 | 82篇 |
1995年 | 72篇 |
1994年 | 49篇 |
1993年 | 30篇 |
1992年 | 35篇 |
1991年 | 24篇 |
1990年 | 16篇 |
1989年 | 18篇 |
1988年 | 16篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 18篇 |
1983年 | 29篇 |
1982年 | 23篇 |
1981年 | 24篇 |
1980年 | 22篇 |
1979年 | 17篇 |
1978年 | 18篇 |
1977年 | 16篇 |
1976年 | 14篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1973年 | 9篇 |
排序方式: 共有5983条查询结果,搜索用时 351 毫秒
11.
Automated currency validation requires a decision to be made regarding the authenticity of a banknote presented to the validation system. This decision often has to be made with little or no information regarding the characteristics of possible counterfeits as is the case for issues of new currency. A method for automated currency validation is presented which segments the whole banknote into different regions, builds individual classifiers on each region and then combines a small subset of the region specific classifiers to provide an overall decision. The segmentation and combination of region specific classifiers to provide optimized false positive and false negative rates is achieved by employing a genetic algorithm. Experiments based on high value notes of Sterling currency were carried out to assess the effectiveness of the proposed solution. 相似文献
12.
13.
树文法是一种高维文法,能够用来表达二维以上复杂对象的构造规则.在模式识别、图式语言等领域有着广泛的应用前景.本文在树文法有关概念基础上提出了标志树、连接标志、标志树文法等概念,构造了标志树的匹配和识别算法,并成功解决了标志树文法的语法分析器构造问题. 相似文献
14.
15.
以地震资料精细处理和解释在大庆长垣外围徐家围子油田开发中的成功应用为例,论述了地震地质综合描述技术在地质情况复杂的低、特低渗透油田开发中的应用效果。 相似文献
16.
语音识别算法的确定与实现 总被引:1,自引:0,他引:1
在语音识别的实验中,对几种算法方案进行了比较、分析和择优淘劣,标准是在一定词汇量的条件下,权衡占用机器的内存空间、(正确)识别率和响应速度。力争使与话者有关的单词语音识别系统的设计达到优化,取得满意的结果。本文即是此项实验的总结。 相似文献
17.
A novel successive learning algorithm based on a Test Feature Classifier is proposed for efficient handling of sequentially provided training data. The fundamental characteristics of the successive learning are considered. In the learning, after recognition of a set of unknown data by a classifier, they are fed into the classifier in order to obtain a modified performance. An efficient algorithm is proposed for the incremental definition of prime tests which are irreducible combinations of features and capable of classifying training patterns into correct classes. Four strategies for addition of training patterns are investigated with respect to their precision and performance using real pattern data. A real-world problem of classification of defects on wafer images has been dealt with by the proposed classifier, obtaining excellent performance even through efficient addition strategies. 相似文献
18.
The tree representation of evolutionary relationship oversimplifies the view of the process of evolution as it cannot take into account the events such as horizontal gene transfer, hybridization, homoplasy and genetic recombination. Several algorithms exist for constructing phylogenetic networks which result from events such as horizontal gene transfer, hybridization and homoplasy. Very little work has been published on the algorithmic detail of phylogenetic networks with constrained recombination. The problem of minimizing the number of recombinations in a phylogenetic network, constructed using binary DNA sequences, is NP-hard. In this paper, we propose a pattern recognition-based O(n2) time approach for constructing the phylogenetic network, where n is the number of nodes or sequences in the input data. The network is constructed with the restriction that no two cycles in the network share a common node. 相似文献
19.
李涛 《信息技术与信息化》2007,10(3):76-78
版面分析过程可以理解为同模式类对象间聚类(合并)的过程,而这种聚类存在的风险(hazard)是伴随整个聚类过程中的。而且越是在后期,该风险值越高,即一旦出现聚类错误则将导致前期正确的聚类结果付诸东流。该文将就此问题展开关于版面分析中的聚类稳定性问题的探讨,并提出相应的逻辑规则——逻辑判别函数(logic differentiation function)用来指导聚类和其在聚类算法中的应用;实验结果表明,建立在定性分析基础上的该规则能解决聚类过程的稳定性问题,同时该规则可以应用在存在若干模式类对象聚类的场合中。 相似文献
20.
Guay Stéphane; Boisvert Jean-Marie; Freeston Mark H. 《Canadian Metallurgical Quarterly》2003,15(3):392
The goal of this study was to examine whether data from 3 different measures of communication (i.e., self-report, quasi-observational, and observational) can predict relationship adjustment and stability 1 year later when used conjointly in a sample of 62 young couples. The 3 measures of communication were the Communication Skills Test-Revised (CST-R), the Communication Box (CB), and the Demand/Withdraw Pattern Questionnaire (DWPQ). Through hierarchical multiple regression analyses, results revealed that the CST-R and the DWPQ predict both genders' relationship adjustment 1 year later when used conjointly. Logistic regression analyses revealed that none of the measures of communication significantly predicted relationship stability. In conclusion, the combination of the CST-R and the DWPQ appears to be useful for longitudinally predicting relationship adjustment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献