Perhaps you should try some spelling variations:
commercial crops » commercial code, commercial credit, commercial banks
based collective » banks collective, based reflective, based selective
earlier studies » early studies
care studies » case studies, career studies, scale studies
act based » fact based, ict based, aet based

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

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