Perhaps you should try some spelling variations:
"biochemical characterization" » "chemical characterization", "mechanical characterization"
"physical characterization" » "chemical characterization", "physical characteristics", "mechanical characterization"
"material characterization" » "materials characterization", "chemical characterization"
"optical characterization" » "chemical characterization", "functional characterization", "mechanical characterization"

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: (("physical characterization") OR ((((("optical characterization") OR ("material characterization"))) OR ("biochemical characterization")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"physical characterization\") or (((((\"optical characterization\") OR (\"material characterization\"))) or (\"biochemical characterization\"))))".
• Removing quotes may allow a broader search: (( physical characterization ) or ((((( optical characterization ) OR ( material characterization ))) or ( biochemical characterization )))).
• Adding a wildcard symbol may retrieve word variants: (("physical characterization") or ((((("optical characterization") OR ("material characterization"))) or ("biochemical characterization"))))*.