Perhaps you should try some spelling variations:
interaction series » interactions series, interaction studies, interaction terms
trade interaction » trade integration, face interaction, time interaction
support land » support plans, support long, support add
import trade » export trade, import price, import taxes
conservation » construction

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: (( support land conservation efforts. ) OR ( import trade interaction series. ))~.
• Adding a wildcard symbol may retrieve word variants: (( support land conservation efforts. ) or ( import trade interaction series. ))*.