Perhaps you should try some spelling variations:
investment periods » investment period, investment series, investment operations
rate investment » rates investment, trade investment, water investment
investor demand » investment demand
bank investor » bank investors, bond investor, bond investors
heat rate » death rate, flat rate
pt bank » post bank

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( h. heat rate investment periods ) OR ( h. pt bank investor demand ))~.
• Adding a wildcard symbol may retrieve word variants: (( h. heat rate investment periods ) or ( h. pt bank investor demand ))*.