Boolean Searches
Operator Summary
|
+ |
Require that a word appear in results |
|
- |
Require that a word NOT appear in results |
|
“ ” |
Search for a specific phrase |
|
() |
Group search into subexpressions |
|
> |
Make a word more important than usual when considering relevance |
|
< |
Make a world less important when considering relevance |
The difference between a regular search and a
Boolean search.
A search
becomes a boolean search when you include any of the above operators
that aim to narrow your results. In general, a search without
operators will take your phrase and attempt to match it up in a smart
way to a field of your choice, computing a relevancy value as it does
so. A search for “glucose ring formation,” for example,
will return results that have to do with all three words as the most
relevant (if they exist), and results that have to do with only
“glucose” or “formation” as less relevant
results. This is often nice for a starting point, but there is
certainly a need to focus your results.
Boolean searches allow you to narrow these results by requiring that specific words or phrases be included or excluded in the fields you are searching. Say, for example, your search for “glucose ring formation” returned a lot of results talking about galactose and maltose, which aren’t in this particular instance of interest to you. You could narrow your results by constructing your query as follows:
glucose ring formation -galactose -maltose
Similarly, you might find that results have a lot to do with the formation of compounds, but not necessarily glucose rings. In that case, you would probably want to require the presence of “glucose” in your results:
+glucose ring formation -galactose -maltose
This is, in reality, a hypothetical example, and what you would probably really want to do is search for “glucose ring” as a specific phrase:
“glucose ring” -galactose -maltose
Hopefully this is enough to help you get meaningful results.
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