Perhaps you should try some spelling variations:
observational techniques » interventional techniques
computational techniques » computing techniques
observational context » observational concepts, observational contacts, observation content
observation concepts » observation concept, observational concepts, conservation 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 techniques) OR (computational techniques))) OR (((observation concepts) OR (observational context)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((observational techniques) OR (computational techniques))) or (((observation concepts) or (observational context))))".
• Adding a wildcard symbol may retrieve word variants: ((((observational techniques) OR (computational techniques))) or (((observation concepts) or (observational context))))*.