The Advanced/Help section explains how search queries will likely to return based on the keywords and punctuation you use in the search bar.
There are three conditions for keyword searches:
Using single or double quotes around a keyword retrieves exact phrases that match the searched keyword.
Example: If you enter “credit rating” with quotes, the results will contain the exact phrase "credit rating."
Using a keyword without quotes will return results containing the keyword itself or any related terms, such as “credit” or “rating,” as well as “credit rating” in the reports and PDFs.
Using two keywords, one with quotes and one without will return results that contain either or both terms.
Example: If you enter “credit rating” or rating revision, the results will show reports containing either or both keywords.