Perhaps you should try some spelling variations:
hanh dai » hanh tai, vanh dai, thanh dat
hanh dao » lanh dao, thanh dat, thanh dam
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
sach ky » sach y, sach ty, sach kem
cac duc » cac du, cao duc, cac dac
ve cac » va cac, vien cac
sac ky » cac ky, sai 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: tu ((sach ky) or (sac ky)) nang cao hoi. hieu ve cac duc va ((hanh dai) or (hanh dao)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang cao hoi. hieu ve cac duc va ((hanh dai) OR (hanh dao)) cua te.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) nang cao hoi. hieu ve cac duc va ((hanh dai) or (hanh dao)) cua te*.