Perhaps you should try some spelling variations:
database retrieval » data retrieval (Expand search)
retrieval process » retrieval models (Expand search), removal process (Expand search)
decrease toc » decrease of (Expand search), decrease the (Expand search), decreased to (Expand search)
toc database » cor database (Expand search), fc database (Expand search), cog database (Expand search)
decrease pro » decrease or (Expand search), decrease food (Expand search), decrease treg (Expand search)
pro decrease » to decrease (Expand search), or decrease (Expand search), price decrease (Expand search)

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: "(( decrease toc database retrieval process ) OR ( decrease pro decrease NOT decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease toc database retrieval process ) OR ( decrease pro decrease NOT decrease ))*.