Perhaps you should try some spelling variations:
theorem investment » term investment, term investments, more investment
investment demand » investor demand
rates investment » notes investment, rules investment, water investment
rent theorem » renner theorem, kin theorem, last theorem
heat rates » heat rate, death rates, heat waves

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( h. heat rates investment barriers ) or ( h. rent theorem investment demand ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( h. heat rates investment barriers ) OR ( h. rent theorem investment demand )).
• Adding a wildcard symbol may retrieve word variants: (( h. heat rates investment barriers ) or ( h. rent theorem investment demand ))*.