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   155篇
  免费   4篇
电工技术   2篇
综合类   3篇
化学工业   38篇
金属工艺   2篇
建筑科学   7篇
能源动力   2篇
轻工业   29篇
水利工程   1篇
无线电   4篇
一般工业技术   16篇
冶金工业   28篇
自动化技术   27篇
  2023年   1篇
  2022年   9篇
  2021年   11篇
  2020年   6篇
  2019年   9篇
  2018年   5篇
  2017年   4篇
  2016年   4篇
  2015年   2篇
  2014年   5篇
  2013年   7篇
  2012年   4篇
  2011年   14篇
  2010年   6篇
  2009年   9篇
  2008年   9篇
  2007年   8篇
  2006年   9篇
  2005年   5篇
  2004年   4篇
  2003年   4篇
  2002年   1篇
  2001年   1篇
  1998年   5篇
  1997年   5篇
  1995年   2篇
  1994年   3篇
  1993年   2篇
  1989年   1篇
  1986年   1篇
  1985年   1篇
  1977年   1篇
  1970年   1篇
排序方式: 共有159条查询结果,搜索用时 15 毫秒
51.
The home-based intervention program Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) was tested in a randomized controlled trial with 237 families screened for their 1- to 3-year-old children's relatively high scores on externalizing behavior. VIPP-SD, based on attachment theory and coercion theory, focuses on mirroring and discussing actual parent-child interactions in six 1.5-hr sessions with individual families at home. VIPP-SD proved to be effective in enhancing maternal attitudes toward sensitivity and sensitive discipline and in promoting sensitive discipline interactions in the intervention group as compared with the control group. Moreover, in families with more marital discord and in families with more daily hassles, the intervention resulted in a decrease of overactive problem behaviors in the children. The authors conclude that VIPP-SD should become an important module in attachment-based interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
52.
ABSTRACT

Stress-relieving heat treatment has been reported to deplete the corrosion resistance of new low-lead and lead-free brass alloys. How the heat treatment, processing and material composition relates to the microstructure and corrosion performance is not well understood. The present study aims to fill this knowledge gap by mapping stress-relieving annealing conditions and different standardised compositions to their respective microstructures and dezincification performance. It was found that loss of corrosion resistance was only the most severe for alloys with higher aluminium and iron content. These alloys displayed significant precipitation of intermetallic aluminium arsenide particles on grain boundaries, twins and lead particles, as well as the formation of β-phase along grain boundaries.

This paper is part of a Thematic Issue on Copper and its Alloys.  相似文献   
53.
Cationized kappa-carrageenans containing 2-hydroxy-3-(trimethylammonium)propyl groups with various degrees of substitution (0.13–0.75) were synthesized by reaction of sulfated polysaccharides with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (QUAB 188) in alkaline solutions through the generation of the corresponding 2,3-epoxy reagent in situ. The structure of the modified algal polysaccharides was characterized without any further treatment or after methanolysis and/or enzymatic depolymerization, by means of spectroscopic tools (FT-IR, NMR, Mass spectrometry) and high-performance size exclusion chromatography (HPSEC). Significant differences in the rheological properties of these cationized kappa-carrageenans have been found depending on the DS values and the presence of KCl salt. Despite their lower molecular weights in comparison with native polysaccharides, cationized kappa-carrageenans with a DS of 0.75 exhibited high viscosity and gelling behaviors mediated by the high density of quaternary ammonium groups.  相似文献   
54.
55.
Herd optimization models that determine economically optimal insemination and replacement decisions are valuable research tools to study various aspects of farming systems. The aim of this study was to develop a herd optimization and simulation model for dairy cattle. The model determines economically optimal insemination and replacement decisions for individual cows and simulates whole-herd results that follow from optimal decisions. The optimization problem was formulated as a multi-level hierarchic Markov process, and a state space model with Bayesian updating was applied to model variation in milk yield. Methodological developments were incorporated in 2 main aspects. First, we introduced an additional level to the model hierarchy to obtain a more tractable and efficient structure. Second, we included a recently developed cattle feed intake model. In addition to methodological developments, new parameters were used in the state space model and other biological functions. Results were generated for Dutch farming conditions, and outcomes were in line with actual herd performance in the Netherlands. Optimal culling decisions were sensitive to variation in milk yield but insensitive to energy requirements for maintenance and feed intake capacity. We anticipate that the model will be applied in research and extension.  相似文献   
56.
Machine learning (ML) has proven to be a useful technology for data analysis and modeling in a wide variety of domains, including food science and engineering. The use of ML models for the monitoring and prediction of food safety is growing in recent years. Currently, several studies have reviewed ML applications on foodborne disease and deep learning applications on food. This article presents a literature review on ML applications for monitoring and predicting food safety. The paper summarizes and categorizes ML applications in this domain, categorizes and discusses data types used for ML modeling, and provides suggestions for data sources and input variables for future ML applications. The review is based on three scientific literature databases: Scopus, CAB Abstracts, and IEEE. It includes studies that were published in English in the period from January 1, 2011 to April 1, 2021. Results show that most studies applied Bayesian networks, Neural networks, or Support vector machines. Of the various ML models reviewed, all relevant studies showed high prediction accuracy by the validation process. Based on the ML applications, this article identifies several avenues for future studies applying ML models for the monitoring and prediction of food safety, in addition to providing suggestions for data sources and input variables.  相似文献   
57.
Although J. Piaget (1968) assumed that children up to 7 years old are unable to consider more than 1 stimulus dimension in their judgments, subsequent research has demonstrated that preschoolers can consider 2 dimensions, such as the width and length of rectangles to estimate their area (F. Wilkening, 1979). The present study addressed the question of whether children can also take 3 stimulus dimensions into account. Kindergartners, 1st and 3rd graders, and adults (N = 73) estimated the volume of cuboids that required the consideration of 3 dimensions: width, height, and length. The results showed that the majority of kindergartners already based their volume estimations on all 3 dimensions. A considerable proportion of kindergartners even integrated width, height, and length multiplicatively. There was no dramatic improvement with age, implying the implicit understanding of volume to develop relatively early in childhood. The results are discussed in light of children’s cognitive competencies concerning multidimensional reasoning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
58.
This study investigated the interaction of child temperament and maternal discipline in the prediction of externalizing problems in early childhood. Interaction effects were evaluated in a sample of 227 one- to three-year-old children with relatively high externalizing problems scores on the Child Behavior Checklist/1 1/2-5. Child temperament was reported by the mothers, maternal discipline was observed in a laboratory session, and child outcome measures included both mother-reported externalizing problems and observed physical aggression. Results indicate that children with difficult temperaments are more susceptible to negative discipline (i.e., they showed more externalizing problems) as well as more susceptible to positive discipline (i.e., they showed fewer externalizing problems and less physical aggression), as compared with children with relatively easy temperaments. These findings provide empirical evidence for the differential susceptibility hypothesis and suggest directions for enhancing the effectiveness of interventions aimed at reducing early childhood externalizing problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
59.
Patients with hemispatial neglect are impaired at moving their attention to a target on the contralesional display side. In the present study, visual display area was varied independently of the number of items displayed within the area. Patients searched for the absence of a simple visual feature in displays that produce serial search performance in normals. The contralesional delay was enhanced for stimulus arrays that were distributed over a larger display area, which suggests that neglect is more severe when attention has to be moved over a larger distance. The directional disengage deficit in neglect therefore depends on the target's relative position within a display, the number of ipsilesional items competing for attention, and the distance of the contralesional attention movements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
60.
Interpersonal misunderstanding is often rooted in noise, or discrepancies between intended and actual outcomes for an interaction partner due to unintended errors (e.g., not being able to respond to an E-mail because of a local network breakdown). How can one effectively cope with noise in social dilemmas, situations in which self-interest and collective interests are conflicting? Consistent with hypotheses, the present research revealed that incidents of noise exert a detrimental effect on level of cooperation when a partner follows strict reciprocity (i.e., tit for tat) but that this effect can be overcome if a partner behaves somewhat more cooperatively than the actor did in the previous interaction (i.e., tit for tat plus 1). Also, when noise was present, tit for tat plus 1 elicited greater levels of cooperation than did tit for tat, thereby underscoring the benefits of adding generosity to reciprocity in coping with noise in social dilemmas. The Discussion outlines implications of the present work for theories focusing on self-presentation and attribution, communication, and trust and prorelationship behavior. (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