Most databases have ways to account for endings of words (truncation) or to substitute for letters (wild cards). Most databases will use * (the asterisk) to be added to the root of the word to account for variations in endings:
manage* will find management or managing or manager or managers or managed or manages - you get the idea.
Most will also use ? to substitute for a letter
defen?e
manage?
Check the Help on the database to make sure you're using the correct symbol for truncation or letter substitution.
In the 3 Psychology databases on EBSCOHost (PscyINFO, PsycARTICLES, and PsycCRITIQUES), the truncation symbol is the asterisk * the single letter substitution wildcard is the question mark ? . There is also the pound sign # which allows for alternate spelling that may include another character. For example colo#r finds both color and colour.
PubMed does NOT encourage truncation, since using the truncation symbol (the asterisk * ) automatically turns off Automatic Term Mapping (PubMed finds a match for your terms in subject headings. If no match found, each word is then searched separately. If still there is no match, words are searched with "and" in all fields). For details on PubMed searching, see the PubMed tutorial. There is no single letter substitution or wildcard in PubMed.