The SEArch engine is 'intelligent'. If you enter 'breath' it will find 'breath, breathe, breathing, breathed' and so on.
However, American v. British spelling can be tricky, and it is best to use wildcards: if you are looking for 'pressurize/pressurise', enter 'pressuri*' as your search term.
If searching for more than one word, use the 'any' or 'all' option. 'All' means that every entered word must occur in the result
To search for a page that contains one word but not another, put a minus sign in front of the word you don't want, for instance "dog -cat" if you want to find documents that contain the word 'dog' but don't contain the word 'cat'.
SEArch the site
Enter one or more keywords to use the SEArch Engine.
Note that '*' wildcards are supported.