Information on how to use the Debian search engine
The Debian search engine at https://search.debian.org/ will allow for different types of searching, depending on what you would like to do.
The simplest way of all is to enter a single word in the search box, and hit enter (or click the Search button). The search engine will then return all pages on the website that have that word in it. This will give you good results quite often.
The next level up is to search for more than one word, which will return you a list of pages on the website that contain all the words you typed.
If a simple search is not enough, then Boolean may do the job for you. You have a choice of AND, OR, NOT and a combination of these three. Note that these operators must be written with all capital letters to be recognised.
AND will return results where both words are in the page. For example "gcc AND patch" will find any pages which contain both "gcc" and "patch". This example gives the same results as "gcc patch", but explicit AND can be useful in combination with other operators.
OR will return results where either word is in the page. For example "gcc OR patch" will find any pages which contain either "gcc" or "patch".
NOT excludes a word from the results. For example "gcc NOT patch" will find all pages which contain "gcc" that do not also contain "patch". You can also write "gcc AND NOT patch" for the same result, but searching for just "NOT patch" is not supported.
(...) can be used to groups subexpressions. For example "(gcc OR make) NOT patch" will find all pages which contain either "gcc" or "make" but do not contain "patch".