全文获取类型
收费全文 | 440篇 |
免费 | 27篇 |
国内免费 | 19篇 |
专业分类
电工技术 | 16篇 |
技术理论 | 1篇 |
综合类 | 23篇 |
化学工业 | 28篇 |
金属工艺 | 3篇 |
机械仪表 | 23篇 |
建筑科学 | 20篇 |
矿业工程 | 7篇 |
能源动力 | 8篇 |
轻工业 | 20篇 |
水利工程 | 3篇 |
石油天然气 | 18篇 |
武器工业 | 2篇 |
无线电 | 19篇 |
一般工业技术 | 101篇 |
冶金工业 | 55篇 |
原子能技术 | 2篇 |
自动化技术 | 137篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 17篇 |
2015年 | 10篇 |
2014年 | 19篇 |
2013年 | 64篇 |
2012年 | 19篇 |
2011年 | 29篇 |
2010年 | 28篇 |
2009年 | 28篇 |
2008年 | 28篇 |
2007年 | 23篇 |
2006年 | 28篇 |
2005年 | 14篇 |
2004年 | 21篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 8篇 |
2000年 | 14篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1965年 | 2篇 |
1963年 | 2篇 |
1961年 | 1篇 |
1956年 | 3篇 |
1954年 | 1篇 |
排序方式: 共有486条查询结果,搜索用时 0 毫秒
31.
一种基于贝叶斯网络的雷达重频模式识别方法 总被引:1,自引:0,他引:1
雷达重频模式指雷达脉冲重复间隔(PRI)的调制样式,重频模式识别对于雷达型号、类别识别具有重要支持作用,但这是一个较困难的过程,一般难以通过单一重频特征完成多种复杂重频模式的自动识别。本文为解决雷达多重频模式自动识别及识别抗噪声干扰问题,针对多种重频模式提取了几种PRI序列特征量(重频特征),然后引入了贝叶斯多网络分类器(BMNClassifier),利用所提取的特征量作为贝叶斯多网络分类器输入节点,通过贝叶斯多网络分类器的概率推理能力来实现雷达重频模式识别。 相似文献
32.
There is a long history of attempts to explain why music is perceived as expressing emotion. The relationship between pitches serves as an important cue for conveying emotion in music. The musical interval referred to as the minor third is generally thought to convey sadness. We reveal that the minor third also occurs in the pitch contour of speech conveying sadness. Bisyllabic speech samples conveying four emotions were recorded by 9 actresses. Acoustic analyses revealed that the relationship between the 2 salient pitches of the sad speech samples tended to approximate a minor third. Participants rated the speech samples for perceived emotion, and the use of numerous acoustic parameters as cues for emotional identification was modeled using regression analysis. The minor third was the most reliable cue for identifying sadness. Additional participants rated musical intervals for emotion, and their ratings verified the historical association between the musical minor third and sadness. These findings support the theory that human vocal expressions and music share an acoustic code for communicating sadness. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
Explanations of working memory span in children were studied in a longitudinal follow-up of J. N. Towse, G. J. Hitch, and U. Hutton (1998). Reading span and operation span were lower when within-task retention intervals were lengthened. For each task, variation in span between test waves and age cohorts was systematically related to changes in processing speed. The two spans explained substantial shared variance in both reading and arithmetic scores, with some evidence for domain specificity. Combined span scores predicted unique variance in scholastic attainment over a 1-year interval. The authors concluded that working memory span is constrained by rapid loss of active codes and is not simply a measure of capacity for resource sharing. Working memory is also implicated in scholastic development. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
34.
Robust Learning with Missing Data 总被引:8,自引:0,他引:8
This paper introduces a new method, called the robust Bayesian estimator (RBE), to learn conditional probability distributions from incomplete data sets. The intuition behind the RBE is that, when no information about the pattern of missing data is available, an incomplete database constrains the set of all possible estimates and this paper provides a characterization of these constraints. An experimental comparison with two popular methods to estimate conditional probability distributions from incomplete data—Gibbs sampling and the EM algorithm—shows a gain in robustness. An application of the RBE to quantify a naive Bayesian classifier from an incomplete data set illustrates its practical relevance. 相似文献
35.
The standard R&R study for evaluation of measurement systems assumes that participating observers constitute a random sample. Often there are only a few observers, all of them included in the study. An alternative measure for the gauge R&R is proposed for this situation, and it is shown that this may improve the perception of the quality of the measurement system markedly, especially with only a few observers. Finally it is shown that a simple estimator can be used, with a bias limited to just a few percent. 相似文献
36.
Objective: This article presumes familiarity with the basics of multiple regression and correlation (MRC) methods and addresses recent controversies and emerging innovations. Areas of emphasis include linking analyses to theory-driven hypotheses, treatment of covariates in hierarchical regression models, recent debates about the testing of mediator and moderator hypotheses, and incorporating confidence intervals into reports of findings using MRC. Conclusions: Two important conceptual innovations (linking analyses closely to theory-derived hypotheses; focusing interpretations on effect sizes and confidence intervals rather than p values) can increase the scientific yield for researchers making use of MRC methods in rehabilitation psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
37.
38.
The effects of two different rolling methods and three tea plucking seasons on alkaloids and phenolics, mainly flavan‐3‐ols and theaflavins, in black tea were studied using an improved high‐performance liquid chromatographic method. Better separation of all tea compounds analyzed—the most important factor for their identification and quantitation—was achieved only with long elution gradients, which overcame the limitations of previously reported methods. Precision of the assay method was very high since intra‐day and inter‐day variations were within 0.76% and 1.66%, respectively. All analytes exhibited good linearity over the range evaluated with a correlation coefficient of 0.9987–1.000. Among the four solvents evaluated, 80% methanol was the most solvent for extracting individual tea compounds. The extraction method applied exhibited good repeatability (CV: 0.39–3.29%). The content of tea compounds analyzed varied with processing method and plucking season. Teas processed using the Cay‐Kur method contained higher levels of identified phenolic compounds than orthodox teas, but their alkaloid content was similar to each other. The most abundant alkaloid in teas was caffeine, ranging from 17.84 mg g?1 dry weight in September plucking to 23.79 mg g?1 dry weight in May plucking. With respect to phenolic compounds, theaflavins were at the highest level, 14.27 mg g?1 dry weight, in Cay‐Kur tea processed in May. Copyright © 2007 Society of Chemical Industry 相似文献
39.
应用于BOSS系统的自动化回归测试技术研究 总被引:1,自引:0,他引:1
本文介绍了一种应用于BOSS系统的自动化回归测试方案,包括该方案的需求背景、系统架构、主要模块及运行流程,并对该方案的实施结果进行了总结。 相似文献
40.