Perhaps you should try some spelling variations:
representation clear » representation great, representation theory, representation scheme
commercial across » commercial crops, commercial actors, commercial crisis
fourier based » course based
clear studies » career studies, leaver studies, queer studies
order based » gender 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 across ((order based) or (fourier based)) representation clear studies.~.
• If you are trying to use Boolean operators, they must be ALL CAPS: commercial across ((order based) OR (fourier based)) representation clear studies..
• Adding a wildcard symbol may retrieve word variants: commercial across ((order based) or (fourier based)) representation clear studies.*.