Perhaps you should try some spelling variations:
investment demands » investment demand, investment funds, investment trends
investment rates » investment rate
based investment » fixed investment, best investment, bond investment
heat rates » death rates, heat waves
test based » text based, rest based, trust based
heat rate » flat rate

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) OR (heat rate)) investment rates ) or ( h. test based investment demands ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( h. ((heat rates) OR (heat rate)) investment rates ) OR ( h. test based investment demands )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( h. ((heat rates) OR (heat rate)) investment rates ) or ( h. test based investment demands ))".
• Adding a wildcard symbol may retrieve word variants: (( h. ((heat rates) OR (heat rate)) investment rates ) or ( h. test based investment demands ))*.