Perhaps you should try some spelling variations:
observational astronomy » observations astronomical
observational context » observational concepts, observational contacts, observation content
observational cinema » observational clinical, observational economy, observational case
observational clues » observational aspects, observational results, observational techniques

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: ((((observational astronomy) OR (((observational cinema) OR (observational clues))))) OR (observational context)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((observational astronomy) or (((observational cinema) OR (observational clues))))) or (observational context))".
• Adding a wildcard symbol may retrieve word variants: ((((observational astronomy) or (((observational cinema) OR (observational clues))))) or (observational context))*.