Perhaps you should try some spelling variations:
"chemical measurements" » "physical measurements", "medical measurements", "mechanical measurements"
"physical measurement" » "physical measurements", "clinical measurement", "physiological measurement"
"optical measurement" » "optical measurements", "physical measurements", "inertial measurement"

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