Truncation symbols: search for variations of a word.
e.g. manag* searches for manage, manager, management, managing etc.
Wildcard symbols: use in place of a letter or a string of letters.
e.g. search for the British and American spellings of organise by typing organi?e
Different databases treat truncation and wildcard symbols in different ways. To check what symbols you should use in a particular database, check the help pages. Open the document above for some common examples of truncation and wildcard symbols.
This is a selection of the most relevant databases for this area. You can find a more comprehensive list from the Databases A-Z list which you can filter by subject.