Depending on the database(s) being searched, default fields for unqualified searches may consist of the following: all authors, all subjects, all keywords, all title info (including source title) and all abstracts.
The title of a magazine may also be a default search field.
DE – Heading or Keyword (Phrase Indexed): DE performs an exact search for subject headings and author-supplied keywords describing an article.
SU – Subject Terms (Word Indexed): SU performs a keyword search for geographic terms and subject terms describing a document’s contents.
SU is not an exact string search. For the example provided, the search of “SU marketing” will return all articles that have subject headings that contain only the word “marketing”. In the above example, articles indexed with the heading “Internet marketing” would not be returned.
Notice that the number of results returned is very different in each of the above searches. The DE search is returning results for subject headings and author supplied keywords that are an exact match to the search string (so only when the field contains just “marketing” will a result be returned). The SU search is performing a keyword search for the presence of the search term within a subject heading field (this includes topical headings, geographic headings and proper noun headings).
Note about Relevance Searching
The default search in EBSCO databases searches several fields, including the Article Title, the Abstract, the Subject Headings and Keywords.
The preponderance of terms is weighed to determine which articles are the most relevant.
It makes sense for the author to supply keywords as these are usually captured and included in a generic Keyword field. From there, subject headings and abstracts are created for the citation.
If the author created an article about business strategy and China, by including those words in the Article Title and Keywords, it will become more relevant when that type of search is applied.