Search results in the left column are ranked by the number of series and folders in which your search term appears. The right column ranks search hits according to the relevance of your search term, with greater weight given to collection guides in which your term appears in the name of the collection, collection description, and series titles.
Number of hits
The number of hits shown in parentheses in the left column and in bold in the right column reflect the number of series, subseries, and folders in which your search term appears. Note that this number is different than the number of highlighted terms indicated when you are viewing an individual guide, which will almost always be greater.
For more about how the search works, see the help page