共查询到20条相似文献，搜索用时 708 毫秒
1.
Modeling a century of citation distributions 总被引：1，自引：1，他引：0
The prevalence of uncited papers or of highly cited papers, with respect to the bulk of publications, provides important clues as to the dynamics of scientific research. Using 25 million papers and 600 million references from the Web of Science over the 1900–2006 period, this paper proposes a simple model based on a random selection process to explain the “uncitedness” phenomenon and its decline over the years. We show that the proportion of cited papers is a function of (1) the number of articles available (the competing papers), (2) the number of citing papers and (3) the number of references they contain. Using uncitedness as a departure point, we demonstrate the utility of the stretched-exponential function and a form of the Tsallis q-exponential function to fit complete citation distributions over the 20th century. As opposed to simple power-law fits, for instance, both these approaches are shown to be empirically well-grounded and robust enough to better understand citation dynamics at the aggregate level. On the basis of these models, we provide quantitative evidence and provisional explanations for an important shift in citation practices around 1960. We also propose a revision of the “citation classic” category as a set of articles which is clearly distinguishable from the rest of the field. 相似文献
2.
3.
To explore the citation evolution of papers published in the same year but different month, we selected papers from a discipline (physical geography), a subject (diabetes: endocrine and metabolism) and a journal (Journal of Biological Chemistry) published in 2005 as research objects. These papers were divided into six groups according to the difference in publication month, and we analyzed citations to these papers for the 9 years after publication. The results showed that within 5 years after papers from physical geography were published, the overall differences in citations of papers in different groups were statistically significant (P < 0.05); after that, the differences were not statistically significant. Within 5 years after papers from diabetes (endocrine and metabolism) were published, the overall differences in citations of papers in different groups were statistically significant (P < 0.05); thereafter, the differences were not statistically significant. Within 7 years after papers from the Journal of Biological Chemistry were published, the overall differences in citations of papers in different groups were statistically significant (P < 0.05); thereafter, the differences were not statistically significant. Citations of papers followed the same pattern irrespective of discipline, subject or journal: citations of papers published in the same year but different month were obviously different in the first few publishing years, but as time went on, only the difference in publication month in a calendar year did not affect the papers' longer‐term citation. 相似文献
4.
5.
R.J. Skaer 《Learned Publishing》1991,4(1):9-15
The Company of Biologists Ltd own, print and publish three major biological journals. Since 1983, we have concentrated on introducing ‘automatic’ methods for journal production. Word processor disks now accompany 89% of articles submitted to The Journal of Experimental Biology. By the use of disk translation software and Optical Character Readers, 76% of these articles are now processed automatically. Over the past few years, the availability of computer disks, however, has required substantial changes in editorial and subediting practices to make it economically worthwhile to use the disks submitted. Optical character recognition is a very useful fallback technique when non–standard disks are submitted, but does require absolutely clean copy. Typesetting is still essential for tables, mathematics and papers that have been substantially altered editorially or are on non–standard disks with a poor quality printout. The economics of the use of disks is briefly discussed together with the overall package of changes needed to make it viable. Inevitably the experience that we have gained will be biased by the scientific nature of the work being set; many other fields would be softer options for the use of disks or other automatic production methods. 相似文献
6.
For comparisons of citation impacts across fields and over time, bibliometricians normalize the observed citation counts with reference to an expected citation value. Percentile-based approaches have been proposed as a non-parametric alternative to parametric central-tendency statistics. Percentiles are based on an ordered set of citation counts in a reference set, whereby the fraction of papers at or below the citation counts of a focal paper is used as an indicator for its relative citation impact in the set. In this study, we pursue two related objectives: (1) although different percentile-based approaches have been developed, an approach is hitherto missing that satisfies a number of criteria such as scaling of the percentile ranks from zero (all other papers perform better) to 100 (all other papers perform worse), and solving the problem with tied citation ranks unambiguously. We introduce a new citation-rank approach having these properties, namely P100; (2) we compare the reliability of P100 empirically with other percentile-based approaches, such as the approaches developed by the SCImago group, the Centre for Science and Technology Studies (CWTS), and Thomson Reuters (InCites), using all papers published in 1980 in Thomson Reuters Web of Science (WoS). How accurately can the different approaches predict the long-term citation impact in 2010 (in year 31) using citation impact measured in previous time windows (years 1–30)? The comparison of the approaches shows that the method used by InCites overestimates citation impact (because of using the highest percentile rank when papers are assigned to more than a single subject category) whereas the SCImago indicator shows higher power in predicting the long-term citation impact on the basis of citation rates in early years. Since the results show a disadvantage in this predictive ability for P100 against the other approaches, there is still room for further improvements. 相似文献
7.
以F1000数据库中生物信息学和免疫学近2 000篇文献为样本,多角度探讨WoS与Scopus数据库的优劣,其中包括两个数据库中被引频次的相关性、与F1000因子的相关性、主要评价指标数值及排序的相关性、历年被引累积量与被引总量相关性、多维空间感知图下的指标间相关性。结论指出：虽然各项指标源于WoS与Scopus不同的数据库,但是就被引频次及与F1000因子关系而言,两库具有较好的一致性;两库的主要评价指标,无论是数值抑或是排序,均体现出高度相关。上述结果可为科研评价中两个数据库的替代性和选择性提供借鉴,同时为定位在开源Scopus系统的利用提供有力依据。 相似文献
8.
Contributing factors to long‐term citation count in marine and freshwater biology articles 
下载免费PDF全文
下载免费PDF全文 Researchers have investigated factors thought to affect the total number of citations in various academic disciplines, and some general trends have emerged. However, there are still limited data for many fields, including aquatic sciences. Using papers published in 2003–2005 (n = 785), we investigated marine and freshwater biology articles to identify factors that may contribute to the probability of citation and for cumulative citation counts over 10 years. We found no relationships with probability of citation; however, we found evidence that for those that were cited at least once, cumulative citations were related to several factors. Articles cited by books received more citations than those never cited by books, which we hypothesized to be indicative of the impact an article may have in the field. We also found that articles first cited within 2 years of publication received more cumulative citations than those first cited after 2 years. We found no evidence that self‐citation (as the first citation) had a significant effect on total citations. Our findings were compared with previous studies in other disciplines, and it was found that aquatic science citation patterns are comparable to fields in science and technology but less so to humanities and social sciences. 相似文献
9.
Antonio Quesada 《Journal of Informetrics》2011,5(3):476-480
The Hirsch index and the Egghe index are both numbers that synthesize a researcher's output. The h-index associated with researcher r is the maximum number h such that r has h papers with at least h citations each. The g-index is the maximum number g of papers by r such that the average number of citations of the g papers is at least g. Both indices are characterized in terms of four axioms. One identifies outputs deserving index at most one. A second one establishes a strong monotonicity condition. A third one requires the index to satisfy a property of subadditivity. The last one consists of a monotonicity condition, for the h-index, and an aggregate monotonicity condition, for the g-index. 相似文献
10.
Wichor Matthijs Bramer 《Journal of the Medical Library Association》2016,104(2):143-145
Objective
Google Scholar is often used to search for medical literature. Numbers of results reported by Google Scholar outperform the numbers reported by traditional databases. How reliable are these numbers? Why are often not all available 1,000 references shown?Methods
For several complex search strategies used in systematic review projects, the number of citations and the total number of versions were calculated. Several search strategies were followed over a two-year period, registering fluctuations in reported search results.Results
Changes in numbers of reported search results varied enormously between search strategies and dates. Theories for calculations of the reported and shown number of hits were not proved.Conclusions
The number of hits reported in Google Scholar is an unreliable measure. Therefore, its repeatability is problematic, at least when equal results are needed. 相似文献11.
《Journal of Informetrics》2019,13(2):515-539
Counting of number of papers, of citations and the h-index are the simplest bibliometric indices of the impact of research. We discuss some improvements. First, we replace citations with individual citations, fractionally shared among co-authors, to take into account that different papers and different fields have largely different average number of co-authors and of references. Next, we improve on citation counting applying the PageRank algorithm to citations among papers. Being time-ordered, this reduces to a weighted counting of citation descendants that we call PaperRank. We compute a related AuthorRank applying the PageRank algorithm to citations among authors. These metrics quantify the impact of an author or paper taking into account the impact of those authors that cite it. Finally, we show how self- and circular-citations can be eliminated by defining a closed market of Citation-coins. We apply these metrics to the InSpire database that covers fundamental physics, presenting results for papers, authors, journals, institutes, towns, countries for all-time and in recent time periods. 相似文献
12.
Jon Zabala Borja González-Albo Ana García-García Aurora Garrido-Domínguez José Ignacio Vidal-Liy Luis R. Álvarez-Díez Soledad Hernando-Tundidor Yara Mostazo-Fernández Teresa Abejón 《Learned Publishing》2023,36(2):205-216
This article analyses the review, acceptance and publication dates of a sample of 21,890 articles from 326 Ibero-American scientific journals from all subject areas and countries included in the Latindex Catalogue 2.0 and published between 2018 and 2020 (freely available as an open access dataset). The aim is to discover evaluation and publication times. The evaluation process takes a median of 110 days, the publication process, a median of 82 days, and the whole process, a median of 224 days. Statistical differences are found according to periodicity, subject areas, countries, existence of a printed version and article type (Call for Papers or General articles). From the data we find that the delay in publication is longer than publishers themselves report to the DOAJ. STEM areas present the most similarity in publication patterns, having a higher number of evaluation days (Ed) than publication days (Pd); Arts and Humanities present the opposite pattern, with a higher Pd than Ed. In the case of Social Sciences, the times are similar. General articles and Call for Papers articles differ in terms of Ed, but not Pd, indicating that Call for Papers revisions are faster. 相似文献
13.
《Journal of Informetrics》2023,17(1):101382
The COVID-19 pandemic and its resultant lockdowns have interrupted the way scientists live and work. This nevertheless caused an unforeseen impact of COVID-19: the pandemic substantially increased editorial speed. Here, we causally identify the impact of the pandemic on the editorial decision time, based on a quasi-experimental regression discontinuity (RD) design that compares (N = 339,199) papers submitted in the lead-up to and aftermath of the COVID-19 pandemic. We find that editors make acceptance decisions significantly quicker after the pandemic, reducing the editorial decision time of revised papers by 8.9 days on average. The pandemic, however, has unequal impacts on editors. The results reveal a larger reduction in editorial decision time for editors of high-tier journals, in the field of social science, or with busy work schedules. Finally, our findings also allude to the potential for the increase of editorial speed, and will stimulate policy changes in scientific enterprises that strive for accelerated publishing. 相似文献
14.
Evgenia Vassilakaki 《International Information and Library Review》2013,45(1-2):3-19
AbstractThis study aims to identify, collect and critical review the research literature on Multilingual Digital Libraries in English language from 1997 to 2012.Design/methodology/approach: The present literature review has followed the rules of systematic review. In particular, the identified relevant papers were categorized based on their expressed aim on two core themes, that of system-centered and user-centered studies. The assigned papers were further analyzed and six sub-themes emerged for the system-centered studies and four for the user-centered studies. Additional categorization was also provided according to type of publication.Findings: The literature concerning Multilingual Digital Libraries is vast and mainly focuses on two aspects the “System” and the “Users”. The majority of papers tried to meet the challenges raised for enabling multilingual information retrieval in Digital Libraries. Unfortunately, these efforts undertaken by a small number of researchers or research groups apparently working in isolation and therefore resulting in the development of numerous different tools and techniques. Relatively few studies have focused on the user and aimed to explore users' behavior and expectations when interacting with Multilingual Digital Libraries. As a result, further research is needed to reach to some tangible and usable findings.Originality/value: This literature review captures the diversity of the research conducted regarding multilingual information access and retrieval in Digital Libraries. It organizes the vast literature in comprehensive themes and sub-themes enabling easy access to specific information.Limitations: This study reviews only papers in English due to language restrictions from 1997 to 2012. 相似文献
15.
16.
Somayeh Soleymani Jeffrey Aalders Michelle E. Gahan Tracy Ireland Dennis McNevin 《文物保护研究》2017,62(2):104-113
Despite substantial literature on the dyeing of textiles, there is a lack of research about colouring Japanese mending papers (tissue papers) used for paper conservation purposes. This study investigates the fungal bioreceptivity of Japanese tissue papers after they have been treated with various dyes and pigments. A variety of toning materials including plant dyes, watercolours, acrylic paints, inks, pastels, gouaches, and colour pencils are commonly used by conservators for paper toning purposes. In this study, two Japanese tissue papers (Yukyu-shi and Sekishu Mare) were treated with selected plant dyes, watercolours, and acrylic paints and then inoculated with fungal species. Quantitative real-time polymerase chain reaction (qPCR) was used to quantify the DNA from Aspergillus niger and Penicillium rubrum as a proxy for fungal species abundance before and after inoculation and artificial moist heat ageing. qPCR primers which were universal for fungi amplified DNA from papers inoculated with A. niger and P. rubrum and these species were found to grow less on treated Sekishu Mare and Yukyu-shi papers compared with untreated papers. Sekishu Mare papers treated with artists' acrylic paints were found to be more resistant to fungal growth than similarly treated Yukyu-shi papers. This study suggests that for the best long-term preservation outcomes for paper materials in archives, libraries, galleries, and museums, acrylic paints generally perform better in conservation terms than most plant dyes and watercolours, although most colourants displayed some bioinhibition. 相似文献
17.
Maria J. Grant 《Health information and libraries journal》2017,34(3):263-265
This inaugural virtual issue of the Health Information and Libraries Journal (HILJ) celebrates the contribution of health information in informing health and social care library and information provision. It has been drawn together to reflect the 2010 biennial Health Libraries Group conference theme of Keeping Information Centre Stage Amid Changing Scenery and includes a series of eleven key papers published in the journal over the last two years. This virtual issue mirrors the usual format of a journal issue with a review article, original articles and regular features on Learning and Teaching in Action, Using Evidence in Practice and International Perspectives and Initiatives. All papers included in this virtual issue of Health Information and Libraries Journal are available free online. 相似文献
18.
In the recent debate on the use of averages of ratios (AoR) and ratios of averages (RoA) for the compilation of field-normalized citation rates, little evidence has been provided on the different results obtained by the two methods at various levels of aggregation. This paper provides such an empirical analysis at the level of individual researchers, departments, institutions and countries. Two datasets are used: 147,547 papers published between 2000 and 2008 and assigned to 14,379 Canadian university professors affiliated to 508 departments, and all papers indexed in the Web of Science for the same period (N = 8,221,926) assigned to all countries and institutions. Although there is a strong relationship between the two measures at each of these levels, a pairwise comparison of AoR and RoA shows that the differences between all the distributions are statistically significant and, thus, that the two methods are not equivalent and do not give the same results. Moreover, the difference between both measures is strongly influenced by the number of papers published as well as by their impact scores: the difference between AoR and RoA is greater for departments, institutions and countries with low RoA scores. Finally, our results show that RoA relative impact indicators do not add up to unity (as they should by definition) at the level of the reference dataset, whereas the AoR does have that property. 相似文献
19.
The following seniority-independent Hirsch-type index has been defined. A scientist has index hpd if hpd of his/her papers have at least hpd citations per decade each, and his/her other papers have less than hpd + 1 citations per decade each. In contrast with the original h-index, which steadily increases in time, hpd of a mature scientist is nearly constant over many years, and hpd of an inactive scientist slowly declines. Therefore hpd is suitable to compare the scientific output of scientists in different ages. 相似文献
20.
Andreas H. Jucker & Manuel Berger 《Media History》2014,20(1):67-87
Newspaper preferences for particular formats of speech presentation differ and they change in the course of time. In this contribution we focus on The Times and trace such developments in the formative years of the modern Anglo-American newspapers, from 1833 to 1988. We extracted data from The Times Digital Archive in six samples of roughly 5000 words at intervals of 31 years and analysed the texts manually for instances of reported speech. Our analysis shows that the focus has shifted from the presentation of speech events as coherent wholes in earlier newspapers towards a more selective use of individual statements that summarise an event or characterise it from different angles. And it also shows that the frequency of indirect forms of discourse presentation decreases over the years in favour of direct forms. This gives further support to the claim that in terms of discourse presentation broadsheets slowly develop into the direction spearheaded by tabloids. 相似文献