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Search strategy and technique

Boolean Operators OR / AND

Logical application of Boolean operators allows you to link your search terms, keywords and "key phrases" to first

  • Broaden the scope of your search with the OR operator, then ...
  • Focus that result set with the AND operator.

Boolean operators can be used in nearly all search engines and literature discovery databases including (but not limited to):
QUT Library Search, Engineering VillageScopus, Web of Science (WoS) and Google Scholar.

Broadens / Widens / Extends Narrows / Constrains / Focusses

to broaden your search to encompass alternative terminology use the OR operator to group synonymous alternative keywords, e.g.,

to narrow your search on a specific aspect or facet use the AND operator to introduce an additional concept, thereby focussing your search result, e.g.,

arch OR bridge OR viaduct ((arch OR bridge OR viaduct) AND "strain measurement") 

will return a broad result set containing any of those three synonyms.

The nested Boolean search statement above returns a focussed result set limited to where the additional concept "strain measurement" appears as a phrase.

Nesting of Boolean search terms

Complex searches can be performed by nesting Boolean operations, e.g.,

(masonry OR brick OR stone) AND (arch OR bridge OR viaduct) AND ((strain OR stress) AND measurement)

Other Search Techniques

Truncate a word with an asterisk * wildcard to retrieve variant right-handed grammatical endings, e.g.,

Use parentheses (brackets) to logically group and specify the order in which your search terms should be processed. OR statements get processed before AND statements. Exactly as in Boolean algebra search statements inside the inner most parentheses get executed first. Synonyms and alternate terminology must be grouped together inside parentheses and linked by the OR operator, e.g.,


(arch OR bridge OR viaduct)

will return ...

  • structure
  • structures
  • structural
  • structured


Phrase search
Placing quotation marks around a word string specifies that you are searching for "an exact phrase", a literal string of text, e.g., "strain measurement"

Truncation is an alternative strategy to using the Boolean OR operator. Use with caution to avoid introducing unwanted results. Note: some database search engines use alternative  characters  $   ? to truncate.


Restricting search to specific fields
To achieve greater precision search statements can be restricted to specific fields, typically: keyword, controlled vocabulary subject, abstract and title fields.

Faceted Refinement of Result Set

All the above-mentioned search interfaces feature a left-hand panel that allows you to refine your search result listing, based on fielded data. The facets in the database record typically used to focus a search result set are:

  • Keyword (author supplied key words and phrases);
  • Controlled Vocabulary Subject Term (both Inspec and Compendex databases boast a subject thesaurus);
  • Classification Schema (for both Inspec and Compendex databases);
  • Year of Publication (range, e.g., latest ten years);
  • Language (e.g., restrict your results to English language).
  • Document Type  / Treatment Type
    (e.g., journal article or conference paper. Also the Scopus database has a useful Type = Review to restrict to review articles);

Most search interfaces also permit you to add an extra term to restrict your results. Often searchers add a word that must appear in either the subject / keywords or article title fields, in order to limit to a smaller, more relevant result set.  

Both the Tips for searching and the Use Boolean, wildcards and truncation pages have more advice on creating effective search strategies.

Subjects: Engineering / Chemical process engineering, Engineering / Civil engineering, Engineering / Computer and software systems engineering, Engineering / Electrical engineering, Engineering / Mechanical engineering, Engineering / Mechatronics engineering, Engineering / Medical engineering
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