Perhaps you should try some spelling variations:
investment demands » investment demand, investment funds, investment banks
investment series » investment services, investment barriers, investment treaties
notes investment » does investment, rates investment, forest investment
rate investment » rates investment, trade investment, water investment
heat rate » death rate, flat rate

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. rent notes investment series ) OR ( h. heat rate investment demands ))~.
• Adding a wildcard symbol may retrieve word variants: (( h. rent notes investment series ) or ( h. heat rate investment demands ))*.