Perhaps you should try some spelling variations:
psychological association's » ecological associations, psychological assumptions, sociological association
psychological association » psychological adaptation, psychological consultation, psychological evaluation

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: medical ((psychological association's) OR (psychological association)).
• Adding a wildcard symbol may retrieve word variants: medical ((psychological association's) or (psychological association))*.