Perhaps you should try some spelling variations:
based presentation » based representation, case presentation, brief presentation
presentation care » presentation large, presentation ease, presentation award
across sources » across countries
care studies » case studies, career studies, scale studies
across » agross
cross » gross

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

• Performing a fuzzy search may retrieve terms with similar spellings: commercial ((across sources) or (cross country)) based presentation care studies.~.
• If you are trying to use Boolean operators, they must be ALL CAPS: commercial ((across sources) OR (cross country)) based presentation care studies..
• Adding a wildcard symbol may retrieve word variants: commercial ((across sources) or (cross country)) based presentation care studies.*.