After performing a search:

• Select 'Limit this search' from the search results screen.
• Select the criteria you wish to limit by.
• Select the 'Limit/sort items retrieved using above data'

Search results may be limited by:

• Year of publication
• Material Type
• Monograph/Serial/Index
• Language
• Publisher
• Where item is located
• Words in the title
• Words in the author
• Words in the subject

More tips on searching are available here