<PubmedArticle>
    <MedlineCitation Status="MEDLINE" Owner="NLM">
        <PMID Version="1">17213501</PMID>
        <DateCompleted>
            <Year>2007</Year>
            <Month>04</Month>
            <Day>19</Day>
        </DateCompleted>
        <DateRevised>
            <Year>2018</Year>
            <Month>12</Month>
            <Day>01</Day>
        </DateRevised>
        <Article PubModel="Print-Electronic">
            <Journal>
                <ISSN IssnType="Print">1067-5027</ISSN>
                <JournalIssue CitedMedium="Print">
                    <Volume>14</Volume>
                    <Issue>2</Issue>
                    <PubDate>
                        <MedlineDate>2007 Mar-Apr</MedlineDate>
                    </PubDate>
                </JournalIssue>
                <Title>Journal of the American Medical Informatics Association : JAMIA</Title>
                <ISOAbbreviation>J Am Med Inform Assoc</ISOAbbreviation>
            </Journal>
            <ArticleTitle>A day in the life of PubMed: analysis of a typical day's query log.</ArticleTitle>
            <Pagination>
                <MedlinePgn>212-20</MedlinePgn>
            </Pagination>
            <Abstract>
                <AbstractText Label="OBJECTIVE" NlmCategory="OBJECTIVE">To characterize PubMed usage over a typical day and compare it to previous studies of user behavior on Web search engines.</AbstractText>
                <AbstractText Label="DESIGN" NlmCategory="METHODS">We performed a lexical and semantic analysis of 2,689,166 queries issued on PubMed over 24 consecutive hours on a typical day.</AbstractText>
                <AbstractText Label="MEASUREMENTS" NlmCategory="METHODS">We measured the number of queries, number of distinct users, queries per user, terms per query, common terms, Boolean operator use, common phrases, result set size, MeSH categories, used semantic measurements to group queries into sessions, and studied the addition and removal of terms from consecutive queries to gauge search strategies.</AbstractText>
                <AbstractText Label="RESULTS" NlmCategory="RESULTS">The size of the result sets from a sample of queries showed a bimodal distribution, with peaks at approximately 3 and 100 results, suggesting that a large group of queries was tightly focused and another was broad. Like Web search engine sessions, most PubMed sessions consisted of a single query. However, PubMed queries contained more terms.</AbstractText>
                <AbstractText Label="CONCLUSION" NlmCategory="CONCLUSIONS">PubMed's usage profile should be considered when educating users, building user interfaces, and developing future biomedical information retrieval systems.</AbstractText>
            </Abstract>
            <AuthorList CompleteYN="Y">
                <Author ValidYN="Y">
                    <LastName>Herskovic</LastName>
                    <ForeName>Jorge R</ForeName>
                    <Initials>JR</Initials>
                    <AffiliationInfo>
                        <Affiliation>University of Texas School of Health Information Sciences at Houston, 7000 Fannin St. Suite 600, Houston, TX 77030, USA.</Affiliation>
                    </AffiliationInfo>
                </Author>
                <Author ValidYN="Y">
                    <LastName>Tanaka</LastName>
                    <ForeName>Len Y</ForeName>
                    <Initials>LY</Initials>
                </Author>
                <Author ValidYN="Y">
                    <LastName>Hersh</LastName>
                    <ForeName>William</ForeName>
                    <Initials>W</Initials>
                </Author>
                <Author ValidYN="Y">
                    <LastName>Bernstam</LastName>
                    <ForeName>Elmer V</ForeName>
                    <Initials>EV</Initials>
                </Author>
            </AuthorList>
            <Language>eng</Language>
            <GrantList CompleteYN="Y">
                <Grant>
                    <GrantID>K22 LM008306</GrantID>
                    <Acronym>LM</Acronym>
                    <Agency>NLM NIH HHS</Agency>
                    <Country>United States</Country>
                </Grant>
                <Grant>
                    <GrantID>UL1 RR024148</GrantID>
                    <Acronym>RR</Acronym>
                    <Agency>NCRR NIH HHS</Agency>
                    <Country>United States</Country>
                </Grant>
                <Grant>
                    <GrantID>1UL1RR024148</GrantID>
                    <Acronym>RR</Acronym>
                    <Agency>NCRR NIH HHS</Agency>
                    <Country>United States</Country>
                </Grant>
                <Grant>
                    <GrantID>5K22LM008306</GrantID>
                    <Acronym>LM</Acronym>
                    <Agency>NLM NIH HHS</Agency>
                    <Country>United States</Country>
                </Grant>
            </GrantList>
            <PublicationTypeList>
                <PublicationType UI="D016428">Journal Article</PublicationType>
                <PublicationType UI="D052061">Research Support, N.I.H., Extramural</PublicationType>
                <PublicationType UI="D013485">Research Support, Non-U.S. Gov't</PublicationType>
            </PublicationTypeList>
            <ArticleDate DateType="Electronic">
                <Year>2007</Year>
                <Month>01</Month>
                <Day>09</Day>
            </ArticleDate>
        </Article>
        <MedlineJournalInfo>
            <Country>England</Country>
            <MedlineTA>J Am Med Inform Assoc</MedlineTA>
            <NlmUniqueID>9430800</NlmUniqueID>
            <ISSNLinking>1067-5027</ISSNLinking>
        </MedlineJournalInfo>
        <CitationSubset>IM</CitationSubset>
        <MeshHeadingList>
            <MeshHeading>
                <DescriptorName UI="D000465" MajorTopicYN="N">Algorithms</DescriptorName>
            </MeshHeading>
            <MeshHeading>
                <DescriptorName UI="D016247" MajorTopicYN="N">Information Storage and Retrieval</DescriptorName>
                <QualifierName UI="Q000706" MajorTopicYN="Y">statistics &amp; numerical data</QualifierName>
            </MeshHeading>
            <MeshHeading>
                <DescriptorName UI="D020407" MajorTopicYN="N">Internet</DescriptorName>
            </MeshHeading>
            <MeshHeading>
                <DescriptorName UI="D046650" MajorTopicYN="N">Medical Subject Headings</DescriptorName>
                <QualifierName UI="Q000706" MajorTopicYN="N">statistics &amp; numerical data</QualifierName>
            </MeshHeading>
            <MeshHeading>
                <DescriptorName UI="D039781" MajorTopicYN="N">PubMed</DescriptorName>
                <QualifierName UI="Q000706" MajorTopicYN="Y">statistics &amp; numerical data</QualifierName>
            </MeshHeading>
        </MeshHeadingList>
    </MedlineCitation>
    <PubmedData>
        <History>
            <PubMedPubDate PubStatus="pubmed">
                <Year>2007</Year>
                <Month>1</Month>
                <Day>11</Day>
                <Hour>9</Hour>
                <Minute>0</Minute>
            </PubMedPubDate>
            <PubMedPubDate PubStatus="medline">
                <Year>2007</Year>
                <Month>4</Month>
                <Day>20</Day>
                <Hour>9</Hour>
                <Minute>0</Minute>
            </PubMedPubDate>
            <PubMedPubDate PubStatus="entrez">
                <Year>2007</Year>
                <Month>1</Month>
                <Day>11</Day>
                <Hour>9</Hour>
                <Minute>0</Minute>
            </PubMedPubDate>
        </History>
        <PublicationStatus>ppublish</PublicationStatus>
        <ArticleIdList>
            <ArticleId IdType="pubmed">17213501</ArticleId>
            <ArticleId IdType="pii">M2191</ArticleId>
            <ArticleId IdType="doi">10.1197/jamia.M2191</ArticleId>
            <ArticleId IdType="pmc">PMC2213463</ArticleId>
        </ArticleIdList>
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