Perhaps you should try some spelling variations:
investment period » investment series, investment policy, adjustment period
water investment » water investments, after investment, rates investment
dept water » melt water, ment water, peat water
dept rates » death rates, des rates, deposit rates
heat rates » heat rate, death rates, heat waves

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. dept water investment period ) OR ( h. ((dept rates) OR (heat rates)) payment services ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( h. dept water investment period ) or ( h. ((dept rates) OR (heat rates)) payment services ))~".
• Adding a wildcard symbol may retrieve word variants: (( h. dept water investment period ) or ( h. ((dept rates) OR (heat rates)) payment services ))*.