Perhaps you should try some spelling variations:
"acoustic emissions" » "acoustic emission"
"elastic emissions" » "traffic emissions", "galactic emission"
"enteric emissions" » "toxic emissions"

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("elastic emissions") OR ("enteric emissions"))) OR ("acoustic emissions")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"elastic emissions\") OR (\"enteric emissions\"))) or (\"acoustic emissions\"))".
• Removing quotes may allow a broader search: (((( elastic emissions ) OR ( enteric emissions ))) or ( acoustic emissions )).
• Adding a wildcard symbol may retrieve word variants: (((("elastic emissions") OR ("enteric emissions"))) or ("acoustic emissions"))*.