As of the current version of this help document, the Search function retrieves results based on the page you are on. For example, if you are on the Posts portion of the site, it will apply your query to all the posts in the database vs. if you were viewing Images, it would search all images in the database.
To answer your question, the search capability supports the following operators:
Operator Function no operator
By default (when neither + nor - is specified) the word...