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61.
Wenli Gao 《期刊图书馆员》2016,70(1-4):121-127
This article outlines a methodology to generate a list of local core journal titles by doing a citation analysis and details the process for retrieving and downloading data from Scopus. It analyzes correlations among citation count, journal rankings, and journal usage. The results of this study reveal significant correlations between journal rankings and journal usage. No correlation with citation count has been found. Limitations and implications for collection development and outreach are also discussed.  相似文献   
62.
[目的/意义]确定基于引用关系提取关键文献时各种方法的优缺点、适用场合,从而使用户快速捕捉领域重要文献,掌握领域概貌。[方法/过程]基于文献引用关系,从文献被引频次、文献引用网络、文献共被引网络3个角度,结合HistCite、CiteSpace等软件探讨领域关键文献的识别方法,通过同源数据的实际验证,对不同方法进行判别比较。[结果/结论]基于被引频次的方法更适合选择特定领域中哪些文献对总体文献的科学进步产生重大影响角度提取关键文献,对应的关键文献集合呈现非常分散的特性;基于引用网络的方法更适合从特定领域研究动态提取发展过程中的关键文献,对应的关键文献集合呈现非常明显的集中特性;基于共被引网络的方法更适合从特定领域研究基础角度提取关键文献,对应的关键文献集合呈现较强的集中性,且能发现原始采集中未发现的大量关键文献。  相似文献   
63.
[目的/意义]从学术期刊中抽取其中的理论是对文献进行内容分析的前提,实现理论名称识别的自动化可以提高内容分析的效率。[方法/过程]将理论识别视为一类命名实体识别问题,总结现有的命名实体识别的常用方法,提出一个基于语义泛化思想的命名实体识别方法,选取词性、知网义原等外部知识,采用CRF模型对《情报学报》1822篇论文的标题和摘要进行实验。[结果/结论]实验表明,识别准确率最高达到95.38%,但召回率较低;训练语料规模对性能影响较大,不同程度的语义泛化方法对准确率和召回率有复杂影响。如何选择语义特征、语义标注和语义消歧是需要解决的新问题。  相似文献   
64.
[目的/意义]传统的文献主题提取方法主要是通过关键词、摘要、全文等提取文献的主题内容,使得主题内容不全面或存在"噪音",而从文献内容语义出发,结合引用内容提取文献的主题,能够更加准确地提取出多文档的主题内容。[方法/过程]提出一种面向多文档的基于语义和引用加权的科技文献主题提取算法,利用文献的引用内容和关键词构建Labeled-LDA主题模型,形成文档-主题概率向量,再根据K-means聚类方法聚类文档,提取每类文档集的主题内容。[结果/结论]以PubMed生物医学数据库中的数据作为实验数据,测试该方法的可靠性,结果证明该方法能够准确、全面地提取出多文档的主题内容。  相似文献   
65.
沈从文的时间意识与死亡意识相生相成,构成沈从文“生命哲学”的重要而又特殊的组成部分。他认为时间的魔力巨大,能消融生命,能治疗痛苦,还能造就创作;他的时间意识停留在“过去”,具有“过去式”、“静态化”与“突变性”的特点。  相似文献   
66.
Participation in youth sport is assumed to promote and contribute towards more physically active lifestyles among children and adolescents. The aim of this study was to examine inter-participant variability in objectively measured habitual physical activity (PA) behaviours and sedentary time among youth sport participants and their implications for health. One-hundred-and-eighteen male youth sport footballers (Mean ± s = 11.72 ± 1.60) wore a GT3X accelerometer for 7 days. Average daily PA [min · day?1, in light (LPA), moderate (MPA), vigorous (VPA) and combined moderate-to-vigorous (MVPA)] and sedentary time were calculated. Participants’ body mass index adjusted for age and sex (BMI–standard deviation score), per cent body fat (BF%), waist circumference and cardiorespiratory fitness were assessed. Results revealed that variability in daily PA behaviours and sedentary time (min · day?1) was associated with BMI–standard deviation score [VPA (?), MVPA (?)], BF% [sedentary time (+), VPA (?), MVPA (?)], waist circumference [sedentary time (+), LPA (?)] and cardiorespiratory fitness [sedentary time (?), MPA (+), VPA (+), MVPA (+)]. Whilst sedentary time and MVPA were not related to health outcomes independent of one another, associations with markers of adiposity and cardiorespiratory fitness were stronger for sedentary time. Sedentary time was also significantly positively related to waist circumference independent of VPA. Results demonstrate inter-participant variability in habitual PA and sedentary time among youth sport participants which holds implications for their health. Thus, promoting PA and, in particular, reducing sedentary time may contribute towards the prevention of adverse health consequences associated with a physically inactive lifestyle for children and adolescents active in the youth sport context.  相似文献   
67.
This study presents a worked example of a stepped process to reliably estimate the habitual physical activity and sedentary time of a sample of young children. A total of 299 children (2.9 ± 0.6 years) were recruited. Outcome variables were daily minutes of total physical activity, sedentary time, moderate to vigorous physical activity and proportional values of each variable. In total, 282 (94%) provided 3 h of accelerometer data on ≥1 day and were included in a 6-step process: Step-1: determine minimum wear-time; Step-2: process 7-day-data; Step-3: determine the inclusion of a weekend day; Step-4: examine day-to-day variability; Step-5: calculate single day intraclass correlation (ICC) (2,1); Step-6: calculate number of days required to reach reliability. Following the process the results were, Step-1: 6 h was estimated as minimum wear-time of a standard day. Step-2: 98 (32%) children had ≥6 h wear on 7 days. Step-3: no differences were found between weekdays and weekend days (P ≥ 0.05). Step-4: no differences were found between day-to-day variability (P ≥ 0.05). Step-5: single day ICC’s (2,1) ranged from 0.48 (total physical activity and sedentary time) to 0.53 (proportion of moderate to vigorous physical activity). Step-6: to reach reliability (ICC = 0.7), 3 days were required for all outcomes. In conclusion following a 7 day wear protocol, ≥6 h on any 3 days was found to have acceptable reliability. The stepped-process offers researchers a method to derive sample-specific wear-time criterion.  相似文献   
68.
9.11事件后地缘政治观的反思   总被引:1,自引:0,他引:1  
地缘政治这一传统观念在经济全球化、政治趋向多极化的背景下,遇到了强有力的挑战。9.11事件后美国政府正在重构其地缘逻辑思维。适时提出“时缘政治”和“人缘政治”概念,全面审视世界政治格局。我国应从国家利益出发,积极重构地缘战略格局。  相似文献   
69.
英汉语在“时间是空间”、“时间流逝是运动”、“时间是金钱”、“时间是实体”等主要时间概念隐喻及相应的语言表达形式中虽有很多相同之处,但也存在着差异。这些差异来源于英汉不同的认知和社会文化背景。  相似文献   
70.
Sit–stand workstations offer a potential strategy to reduce prolonged occupational sitting. This controlled intervention study examined the effects of an environmental intervention on occupational sedentary time, musculoskeletal comfort and work ability, and the usability of sit–stand workstations in office work via a self-reported questionnaire. The intervention group (n?=?24) used sit–stand workstations during the 6-month intervention period, and the control group (n?=?21) used traditional sitting workstations. The results showed that working at sit–stand workstations can reduce sitting time significantly compared to control workstations (?6.7% vs. 5.0%, p?=?.019), which is reallocated mostly to standing (r?=??0.719, p?p?=?.028), as well as work ability (p?=?.022). The majority of intervention subjects rated sit–stand workstation adjustability as good (83.3%), and 75.0% were satisfied with the workstation. About 41.7% of the intervention participants, who were exclusively female, used the sit–stand function on a daily basis. While the environmental change alone was effective, it is likely that promoting the daily use of sit–stand workstations with counselling would lead to even more substantial positive effects.  相似文献   
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