The Heidelberg search function combines all specified words with an AND operator - the more words you specify the less results are returned. The Heidelberg search function supports the wildcards "*" and "?". Use the wildcards, if you are not aware of the spelling or if you want to search for word parts. The wildcard "*" represents any number of characters, so that a search for speed*er, matches speedmaster as well as speedster. The wildcards "?" represents a single character, so that a search for m?ster, matches master as well as mister. The Heidelberg search function supports phrases. Whenever you search for a well known phrase, you should enclose the phrase with single quotes, e.g. 'speedmaster sm'. The Heidelberg search function is not case sensitive. Searching for "speedmaster" or "SPEEDMASTER" produces the same results.