Perhaps you should try some spelling variations:
learning resource » learning resources, learning research, teaching resource
resource theories » resource theory, resources series, resource agencies
resources surveys » resource survey, resources series, resources systems
wbi learning » 2 learning, 3 learning
4 learning » 2 learning, 3 learning

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: (( e learning resource theories. ) OR ( ((wbi learning) OR (4 learning)) resources surveys. ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( e learning resource theories. ) or ( ((wbi learning) OR (4 learning)) resources surveys. ))~".
• Adding a wildcard symbol may retrieve word variants: (( e learning resource theories. ) or ( ((wbi learning) OR (4 learning)) resources surveys. ))*.