Perhaps you should try some spelling variations:
"selected supplementary materials" » "selected supplementary material", "required supplementary materials"
"eleven supplementary services" » "eleven supplementary exercises", "level supplementary services", "present supplementary services", "led supplementary services"

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: (("eleven supplementary services") OR ("selected supplementary materials")).
• Removing quotes may allow a broader search: (( eleven supplementary services ) or ( selected supplementary materials )).
• Adding a wildcard symbol may retrieve word variants: (("eleven supplementary services") or ("selected supplementary materials"))*.