Perhaps you should try some spelling variations:
"aaas symposium semi" » "acs symposium semi", "cas symposium semi", "gras symposium semi", "aaas symposium sas", "aaas symposium sss"
"das symposium sagt" » "das symposium sas", "das symposium sss", "das symposion sagt", "bacus symposium sagt", "texas symposium sagt"

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: (("aaas symposium semi") OR ("das symposium sagt"))*.
• Removing quotes may allow a broader search: (( aaas symposium semi ) or ( das symposium sagt ))*.