Perhaps you should try some spelling variations:
dang hoai » dang hai, dang loai, dung hoai
hanh thai » nhanh thai, hinh thai, hanh tai
dua tren » dung tren
hoai hoi » hoa hoi, hoi hoi, ngoai hoi
van hanh » van thanh, ban hanh, van anh
hieu ve » hieu va, hieu van
duc van » duc va, duc tan, duc manh
cao duc » dao duc, cao suc, giao duc
ve cao » va cao, ve bao, ve cac
sac ky » cac ky
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sai ky) or (sac ky)) dang hoai hoi. hieu ve cao duc van hanh thai ((dua tren) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sai ky) OR (sac ky)) dang hoai hoi. hieu ve cao duc van hanh thai ((dua tren) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su ((sai ky) or (sac ky)) dang hoai hoi. hieu ve cao duc van hanh thai ((dua tren) or (cua te))*.