Perhaps you should try some spelling variations:
thien hieu » thien nhien, thien chien, thien hue
dung cuong » dung cong, dung luong, dang cuong
hieu quan » hieu qua, lieu quan, thien quan
tran tuan » tran xuan, tran thanh, tranh luan
cuong tap » luong tap, cong tac, luong tai
toan cau » toan cao, toan ban, toan tai
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: thien hieu quan - thanh ((tran tuan) or (tran quang)) dung cuong tap ((toan cau) OR (toan tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thien hieu quan - thanh ((tran tuan) OR (tran quang)) dung cuong tap ((toan cau) OR (toan tap)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thien hieu quan - thanh ((tran tuan) or (tran quang)) dung cuong tap ((toan cau) OR (toan tap))".
• Adding a wildcard symbol may retrieve word variants: thien hieu quan - thanh ((tran tuan) or (tran quang)) dung cuong tap ((toan cau) OR (toan tap))*.