When searching only exact results are returned when more are expected.
Generally, exact search is invoked by enclosing the search terms with double-quotes(") and this will return very few results.
There are circumstances where the exact search will be invoked without the couble-quotes. This includes if the search terms include a colon(:) or two or more consecutive spaces in a row.
For example, if you are searching for RE: Lunch 2/9. Search should return all entries with RE OR Lunch OR 2/9 but becuase of the colon it returns RE AND Lunch AND 2/9, as if the search term was "RE Lunch 2/9"