Perhaps you should try some spelling variations:
"prospects theory" » "process theory", "prospectos theory", "prospectors theory", "respects theory"
"projects theory" » "process theory", "protection theory"
"project theory" » "process theory", "protection theory"
"prospect theory" » "prospecto theory", "prospector theory", "respect theory"

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"prospect theory\") OR (\"project theory\"))) OR (((\"prospects theory\") OR (\"projects theory\"))))~".
• Removing quotes may allow a broader search: (((( prospect theory ) OR ( project theory ))) OR ((( prospects theory ) OR ( projects theory ))))~.
• Adding a wildcard symbol may retrieve word variants: (((("prospect theory") OR ("project theory"))) OR ((("prospects theory") OR ("projects theory"))))*.