Perhaps you should try some spelling variations:
"iii mechanical material" » "iii mechanics materials", "iii mechanical metamaterials", "iii mechanical scattering", "2 mechanical material", "7 mechanical material", "8 mechanical material"
"iii clinical material" » "iii clinical trial", "iii clinical potential", "iii clinical trials", "ii clinical material"

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

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