Perhaps you should try some spelling variations:
"occupational opportunity" » "occupational opportunities", "occupational mortality", "generational opportunity"
"exceptional opportunity" » "generational opportunity", "relational opportunity", "international opportunity"
"educational opportunity" » "educational opportunities"
"occupational activity" » "occupational toxicity", "occupational accidents", "occupational mortality"
"occupational mobility" » "occupational medicine"

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: (((((("occupational opportunity") OR ("exceptional opportunity"))) OR ((("occupational activity") OR ("occupational mobility"))))) OR ("educational opportunity")).
• Removing quotes may allow a broader search: (((((( occupational opportunity ) or ( exceptional opportunity ))) or ((( occupational activity ) or ( occupational mobility ))))) or ( educational opportunity )).
• Adding a wildcard symbol may retrieve word variants: (((((("occupational opportunity") or ("exceptional opportunity"))) or ((("occupational activity") or ("occupational mobility"))))) or ("educational opportunity"))*.