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   242篇
  免费   10篇
化学工业   54篇
金属工艺   3篇
机械仪表   6篇
建筑科学   10篇
能源动力   3篇
轻工业   23篇
水利工程   2篇
石油天然气   2篇
无线电   11篇
一般工业技术   39篇
冶金工业   37篇
自动化技术   62篇
  2023年   6篇
  2022年   11篇
  2021年   21篇
  2020年   6篇
  2019年   9篇
  2018年   5篇
  2017年   8篇
  2016年   8篇
  2015年   7篇
  2014年   11篇
  2013年   16篇
  2012年   13篇
  2011年   20篇
  2010年   6篇
  2009年   13篇
  2008年   16篇
  2007年   5篇
  2006年   8篇
  2005年   14篇
  2004年   10篇
  2003年   3篇
  2002年   7篇
  2001年   3篇
  2000年   4篇
  1999年   4篇
  1998年   6篇
  1997年   4篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1986年   1篇
排序方式: 共有252条查询结果,搜索用时 15 毫秒
221.
Recent proliferation of camera phones, photo sharing and social network services has significantly changed how we process our photos. Instead of going through the traditional download‐edit‐share cycle using desktop editors, an increasing number of photos are taken with camera phones and published through cellular networks. The immediacy of the sharing process means that on‐device image editing, if needed, should be quick and intuitive. However, due to the limited computational resources and vastly different user interaction model on small screens, most traditional local selection methods can not be directly adapted to mobile devices. To address this issue, we present TouchTone, a new method for edge‐aware image adjustment using simple finger gestures. Our method enables users to select regions within the image and adjust their corresponding photographic attributes simultaneously through a simple point‐and‐swipe interaction. To enable fast interaction, we develop a memory‐ and computation‐efficient algorithm which samples a collection of 1D paths from the image, computes the adjustment solution along these paths, and interpolates the solutions to entire image through bilateral filtering. Our system is intuitive to use, and can support several local editing tasks, such as brightness, contrast, and color balance adjustments, within a minute on a mobile device.  相似文献   
222.
Organizations increasingly use social media and especially social networking sites (SNS) to support their marketing agenda, enhance collaboration, and develop new capabilities. However, the success of SNS initiatives is largely dependent on sustainable user participation. In this study, we argue that the continuance intentions of users may be gender-sensitive. To theorize and investigate gender differences in the determinants of continuance intentions, this study draws on the expectation-confirmation model, the uses and gratification theory, as well as the self-construal theory and its extensions. Our survey of 488 users shows that while both men and women are motivated by the ability to self-enhance, there are some gender differences. Specifically, while women are mainly driven by relational uses, such as maintaining close ties and getting access to social information on close and distant networks, men base their continuance intentions on their ability to gain information of a general nature. Our research makes several contributions to the discourse in strategic information systems literature concerning the use of social media by individuals and organizations. Theoretically, it expands the understanding of the phenomenon of continuance intentions and specifically the role of the gender differences in its determinants. On a practical level, it delivers insights for SNS providers and marketers into how satisfaction and continuance intentions of male and female SNS users can be differentially promoted. Furthermore, as organizations increasingly rely on corporate social networks to foster collaboration and innovation, our insights deliver initial recommendations on how organizational social media initiatives can be supported with regard to gender-based differences.  相似文献   
223.
The goal of the study was to explore the content of on-line and off-line peer interactions among shy and non-shy adolescents. Participants were 148 ten-to-eighteen year old adolescents in Rome, Italy (n = 98) and Ottawa, Canada (n = 50). Participants completed self reports of shyness and loneliness and web logs of their interactions with friends both in person and on-line. Among the results, there was little general difference in the general content and emotion expressed during the two modalities of interaction with friends, both of which were used in a wide variety of ways. Importantly, shy participants used the on-line modality more extensively than their non-shy counterparts to express negative emotions and to convey content regarding negative exchanges with peers. Such use of electronic communication may be an important contributor to their loneliness.  相似文献   
224.
Three methods of synthesizing correlations for meta-analytic structural equation modeling (SEM) under different degrees and mechanisms of missingness were compared for the estimation of correlation and SEM parameters and goodness-of-fit indices by using Monte Carlo simulation techniques. A revised generalized least squares (GLS) method for synthesizing correlations, weighted-covariance GLS (W-COV GLS), was compared with univariate weighting with untransformed correlations (univariate r) and univariate weighting with Fisher's z-transformed correlations (univariate z). These 3 methods were crossed with listwise and pairwise deletion. Univariate z and W-COV GLS performed similarly, with W-COV GLS providing slightly better estimation of parameters and more correct model rejection rates. Missing not at random data produced high levels of relative bias in correlation and model parameter estimates and higher incorrect SEM model rejection rates. Pairwise deletion resulted in inflated standard errors for all synthesis methods and higher incorrect rejection rates for the SEM model with univariate weighting procedures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
225.
Presents the obituary for Winifred Starbuck Scott (1906-2003), who served as American Psychological Association's Division of School Psychology president in 1964-1965. Dr. Scott is noted for her work in the area of school psychology and her extensive involvement in numerous divisions within APA. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
226.
Ferroelectricity is one of the demanded effects in fundamental and applied solid state physics. Till now, the ferroelectrics were available mostly in the inorganic world. The breakthrough of 2000s was an unexpected discovery of the ferroelectricity related to the charge ordering in quasi-1D organic conductors (TMTTF)2X, and in some layered compounds. The achieved understanding of underlying mechanisms allows to speculate on synthesis of a would-be ferroelectric polymer: it must possess a combination of dimerizations of sites and bonds, one of which must be build-in and another spontaneous. The theory of these “combined Peierls states” predicts an existence of solitons (dimerization kinks) with non-integer variable charges—they are the walls separating domains with opposite electric polarization. The physics of these exotic solitons will serve to describe transient processes in ferroelectric polymers, linking optical- and low-frequency properties. The promising example of such an (AB)x conjugated polymer has already appeared but was not yet tested for ferroelectricity. A wide chemical search is necessary because of a problematic competition of an anti-ferroelectric phase, whose occurrence depends on complicated details of the interchain coupling.  相似文献   
227.
Neuropsychological deficits have been reported among trauma survivors with posttraumatic stress disorder (PTSD). It is often assumed that these cognitive difficulties are toxic consequences of trauma exposure. Alternatively, they may reflect preexisting characteristics that contribute to the likelihood of developing PTSD. To address this possibility, the authors evaluated cognitive performance in monozygotic twin pairs who were discordant for combat exposure. Pairs were grouped according to whether the combat-exposed brother developed PTSD. The combat-unexposed cotwins of combat veterans with PTSD largely displayed the same performance as their brothers, which was significantly lower than that of non-PTSD combat veterans and their brothers. The results support the notion that specific domains of cognitive function may serve as premorbid risk or protective factors in PTSD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
228.
This randomized clinical trial evaluated individual cognitive-behavioral therapy (CBT), family therapy, combined individual and family therapy, and a group intervention for 114 substance-abusing adolescents. Outcomes were percentage of days marijuana was used and percentage of youths achieving minimal use. Each intervention demonstrated some efficacy, although differences occurred for outcome measured, speed of change, and maintenance of change. From pretreatment to 4 months, significantly fewer days of use were found for the family therapy alone and the combined interventions. Significantly more youths had achieved minimal use levels in the family and combined conditions and in CBT. From pretreatment to 7 months, reductions in percentage of days of use were significant for the combined and group interventions, and changes in minimal use levels were significant for the family, combined, and group interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
229.
Bayesian networks for system reliability reassessment   总被引:2,自引:0,他引:2  
This paper proposes a methodology to apply Bayesian networks to structural system reliability reassessment, with the incorporation of two important features of large structures: (1) multiple failure sequences, and (2) correlations between component-level limit states. The proposed method is validated by analytical comparison with the traditional reliability analysis methods for series and parallel systems. The Bayesian network approach is combined with the branch-and-bound method to improve its efficiency and to facilitate its application to large structures. A framed structure with multiple potential locations of plastic hinges and multiple failure sequences is analyzed to illustrate the proposed method.  相似文献   
230.
Environmental or abiotic stresses are a common threat that remains a constant and common challenge to all plants. These threats whether singular or in combination can have devastating effects on plants. As a semiaquatic plant, rice succumbs to the same threats. Here we systematically look into the involvement of salicylic acid (SA) in the regulation of abiotic stress in rice. Studies have shown that the level of endogenous salicylic acid (SA) is high in rice compared to any other plant species. The reason behind this elevated level and the contribution of this molecule towards abiotic stress management and other underlying mechanisms remains poorly understood in rice. In this review we will address various abiotic stresses that affect the biochemistry and physiology of rice and the role played by SA in its regulation. Further, this review will elucidate the potential mechanisms that control SA-mediated stress tolerance in rice, leading to future prospects and direction for investigation.  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