Perhaps you should try some spelling variations:
observation efforts » conservation efforts, conservation effort, observation networks
integration theory » integration through, information theory, innovation theory
urban integration » european integration, urban migration, chain integration
ocean observation » ocean conservation, cai observation, cao observation
supply ocean » supply chain, supply oecd, supply chai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply urban integration theory. ) or ( supply ocean observation efforts. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply urban integration theory. ) OR ( supply ocean observation efforts. )).
• Adding a wildcard symbol may retrieve word variants: (( supply urban integration theory. ) or ( supply ocean observation efforts. ))*.