Article Metadata Guide

Search Language


The Article Metadata API supports a Boolean syntax, which is a type of search allowing users to combine keywords with operators such as AND, NOT and OR to further produce more relevant results. For example, a Boolean search could be "heart" AND "brain". This would limit the search results to only those documents containing the two keywords.

URL encoding


The Boolean search is submitted through the query string parameter 'query'. As with all other query string parameters, the contents of the submitted search must be URL-encoded. It should be noted that the '+' character serves a special purpose as a query string value, functioning as an equivalent to the space character (i.e. %20). In order to submit a literal character '+' it must be properly URL-encoded (i.e. %2B).

This search...

must be URL-encoded as:

AFFIL(Harvard AND NOT MIT OR Princeton)


AFFIL(Harvard AND MIT AND NOT Princeton OR Duke)


AFFIL("Rutgers University")




Connectors can be used to search for more than one word in a single search. Words submitted without connectors will automatically be logically connected by an implicit AND connector. When using more than one connector or operator in a search, an order of precedence is applied to the connectors and/or operators (see below).

In order to search for a specific phrase, the terms should be enclosed in double quotes (" ").




AND is the default connector. When you enter 2 or more search terms in a field, AND is automatically inserted between any spaces or hyphens in the terms.


keywords(heart attack) or keywords(heart-attack) would both be searched as keywords(heart AND attack)

Use AND when you want to search for multiple terms in a given field.


keywords(lesion AND pancreatic)


Use OR when at least one of your search terms must appear in a given field. You can use OR to search for synonyms, alternate spellings, or abbreviations.


keywords(kidney OR renal)


Use AND NOT to exclude specific terms from fields.


Do not use AND NOT at the beginning of a search.



keywords(ganglia OR tumor AND NOT malignant) finds documents including the keywords "ganglia" or "tumor", but not the keyword "malignant".


Order of precedence 

Boolean searches with multiple operators are processed using the following order of precedence:

  1. OR
  1. AND
  1. AND NOT
  2. After the precedence rules are applied, the search is read left to right. For example:

    This search...

    is interpreted as:

    AFFIL(Harvard AND NOT MIT OR Princeton)

    AFFIL((Harvard) AND NOT (MIT OR Princeton))

    AFFIL(Harvard AND MIT AND NOT Princeton OR Duke)

    AFFIL((Harvard AND MIT) AND NOT (Princeton OR Duke))

    All these searches:

    • AFFIL(Harvard OR MIT AND Princeton)
    • AFFIL(Harvard AND MIT OR Princeton)
    • AFFIL(Harvard OR MIT AND Princeton)

    are processed as:

    AFFIL((Harvard OR MIT) AND Princeton)



    AND NOT can give unexpected results when you have multiple operators. We recommend that you put it at the end of your searches.

    For example, the following search returns a large number of results:

    keywords(cold AND NOT influenza AND rhinovirus)

    To exclude influenza from your search and make it more targeted, use the following instead:

    keywords(cold AND rhinovirus AND NOT influenza)

    Field Restriction


    Search criteria must be restricted to specific portions of documents using fields names. The Article Metadata API does NOT support general search criteria; all searches must use field restrictions.


    affil(Harvard) finds all the documents that contain "Harvard" in their affiliation elements.

    Field Search Tips


    Where search_term is the term you want to find and field_name is one of the fields in the field name table.

    Field name abbreviations, where available, are listed below in the Abbreviation column.

    Field Name





    Permits keyword searches for documents. This field accepts phrases and can be used with Boolean operators. Example: keywords("bacteria")

    Note: this field searches only indexed keywords, not the document full text.



    Contains the category of content associated with the document. Content designations use the following abbreviations:

    • JL - Journals
    • BS - Book Series
    • HB - Handbook Series
    • BK - eBook
    • RW - Major Reference Works

    Combinations of content can be OR-ed together. For example, the following qualifies against all serial content:

    content-type(JL OR BS OR HB)



    Contains the names of the authors of the document.



    Contains the institutional or corporate address of the article's authors.



    Contains the date the document was published in numeric format. To search for a specific date using Pub-Date, you must use one of the following date operators:

    • BEF or <: Before
    • AFT or >: After
    • IS or =: Is equal to


    • pub-date AFT 20060103 finds documents published after January 3, 2006.
    • pub-date BEF 20060103 finds documents published before January 3, 2006.



    Contains the English or non-English article or chapter title.



    Contains the title of the journal, book, book series, handbook, or Reference Work.



    Contains the Digital Object Identifier (DOI). A DOI is a unique alphanumeric string created to identify a piece of intellectual property in an online environment.

    You should enter DOIs with the appropriate formatting; however, you can enter partial DOIs. For example, you could enter the DOI 10.1016/j.cor.2005.08.013 as 10.1016 or j.cor.2005.08.013.



    Contains the ISSN (International Standard Serial Number) of the series.

    ISSN values must be entered without hyphens. For example, you must enter ISSN 0305-0548 as 03050548.



    Contains the ISBN (International Standard Book Number) of the book, Reference Work, or a volume in a series.

    ISBN values must be entered without hyphens. For example, you must enter ISBN 978-0-444-52259-7 as 9780444522597.



    Contains the volume and/or issue identifiers for a serial publication.



    Contains the date that the document was first loaded onto ScienceDirect. The format to be used is YYYYMMDD. For example, available-online-date(20140129) returns documents that were first loaded onto ScienceDirect on January 29, 2014.

    To search in combination with BEF and AFT, combine the operators with the field name, e.g. available-online-date AFT 20140129



    Contains the date that the version of record was first loaded onto ScienceDirect. The format to be used is YYYYMMDD. For example, vor-available-online-date(20140129) returns documents that were first loaded onto ScienceDirect on January 29, 2014.

    To search in combination with BEF and AFT, combine the operators with the field name, e.g. vor-available-online-date AFT 20140129



    Contains binary value indicating open access status. For example, openaccess(1) returns open access documents, whereas openaccess(0) returns non-open access documents.