Perhaps you should try some spelling variations:
than quoc » han quoc, tran quoc, toan quoc
hang hai » hoang hai, hang tai, thanh hai
hai khoi » mai khoi, tai khoi, thai khoa
qua than » qua thanh, qua phan, qua tan
thanh vi » hanh vi, thanh va, thanh ve
va triet » va thiet, ve triet, cua triet
va trien » va truyen, va thiet, va tuyen
vu khao » va khao, vu kham, vu khac
khao ly » khanh ly
ly hang » ly quang
gia » giao

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu khao ly hang hai khoi. hieu qua than quoc gia thanh vi ((va triet) or (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu khao ly hang hai khoi. hieu qua than quoc gia thanh vi ((va triet) OR (va trien)).
• Adding a wildcard symbol may retrieve word variants: vu khao ly hang hai khoi. hieu qua than quoc gia thanh vi ((va triet) or (va trien))*.