If you wish to undertake a more systematic/comprehensive search, you need to think about all of the possible synonymous terms that could be relevant for your research questions and how you would combine these.
A simple example of the above could be:
You combine your search terms with AND, OR, NOT. Use the tabs to find out more.
Each database may work differently, always consult the search help (or get in touch) if you are unsure or if you are not getting the results you had hoped for.
AND
If you don't specify, most databases will AND your terms together. Example:
Search = [marine biology]
Results:
= only those results in intersection 3 (i.e. that have both search terms)
OR
Should be used where you need to find any variations of the same word. You need to tell the database that you want to OR your terms. Example:
Search = [ocean or marine]
Results:
= any search results that have either keyword 1, or keyword 2 or both keywords (intersection 3)
NOT
This operator can be used to exclude irrelevant results, but should be used with caution. Example:
Search = [solar not wind]
Results:
= results from section 1 only excluding results that contain keyword 2, but also excluding those results that contain 1 and 2 (intersection 3) so possibly excluding relevant results
Many databases allow the use of proximity operators, which specify how many words apart your keywords should be:
Note: You cannot use the AND operator as an argument to a proximity expression.
Note: You cannot use the AND operator in queries that include the NEAR operator.
Other databases
Each database may differ, so check if proximity operators are allowed and how to use them.
Sometimes you might want to force a phrase search e.g. rather than searching for [building and information and modelling] you want it to search for ["building information modelling"]
Think carefully about using exact phrase match e.g. “carbon emission reduction” would not find “reduction of carbon emissions”
Most databases allow "phrase searching". Scopus also has an {exact phrase match} where you can put your phrase in curly brackets. Again, be careful with this as it may exclude relevant results.
If you don't want to phrase search then you might want to consider proximity operators (see tab above).
Once you have decided on all of your synonymous terms and abbreviations, you should group them together as one search, e.g.:
Search 1:
[fish* or invertebrate* or scallop* or lobster*]
Search 2:
[“marine reserve*” or “marine area” or MPA]
You can then use the database functionality to combine your searches, e.g.:
Search 3:
search#1 AND search #2
This is equivalent to a search for:
(fish* or invertebrate* or scallop* or lobster*) and (“marine reserve*” or “marine area” or MPA)
It is better to split your search this way, rather than doing one search for (fish* or invertebrate* or scallop* or lobster*) and (“marine reserve*” or “marine area” or MPA). Splitting it makes it easier to identify any errors and to edit your search, should you think of additional terms.
Many databases use subject headings, thesaurus and/or controlled vocabulary, that can help identify keywords/search concepts. It is also possible to 'explode' a concept to include all variants. Get in touch for further details.
It is likely that you will need to search across multiple databases and adapt your search strings to each database. You will need to balance search sensitivity and specificity (depending on your project scope).
It is important to keep track of your searches and we recommend registering with the database so you can save your searches.