When there are more than one search term, the result contains at
least one of them.
To make any term mandatory, use a plus sign as prefix. Example:
+kind love for posts with “kind” and maybe
“love”.
To exclude a term, use a minus sign. Example:
love -friend for posts with “love” but not “friend”.
You can confine a term to a specific field. Supported fields are
“author”, “title”, and “content”. Example: title:love
searches for “love” in the title only.