Within search boxes:

• Search terms are automatically joined by 'and'
  (wheat elevator finds wheat and elevator)
• Use / for OR
  (wheat / elevator)
• Use ! for NOT
  (wheat! elevator)
• Use " " to search for a phrase
  (e.g. "train engine")
• In the Keyword search truncation is automatic
  (e.g. elevat finds
  elevator,
  elevated, etc.)

Special Characters:

• Use * to truncate
  (e.g. rail* finds
  railroad,
  railway, etc.)
• Use >, <, >=, <= for greater or less than
  (e.g. <= 1999 finds dates earlier than 1999 inclusive)
• Use : to search a range
  (e.g. 1999:2003, example:sample)