Words may be right-hand truncated using an asterisk * in place of other characters.
aquacult* - aquaculture(s) aquacultural, aquaculturalist(s) ...
fish* - fishes, fishery, fisheries, fishing, fisherman ...
The * wildcard may also be embedded in a search string.
? replaces a single character anywhere within a word.
Use "and" or "or" to specify multiple words in any field, any order. Use "not" to exclude words.
fisheries and hake
(river or stream) and (fishes not trout)
How Library Stuff Works: How to Choose Keywords
(video from McMaster University)
Try it for your yourself by linking to the three subject headings for this book.