Perhaps you should try some spelling variations:
observational context » observational concepts, observational contacts, observationsin contexts
observational errors » observational methods, observational method
observational cohort » observational support, observational methods, observational method
observational clues » observational aspects, observational results, observational techniques
observation content » observation concept, observation consistent, observation concepts

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