Perhaps you should try some spelling variations:
thieu nien » thien nhien
hieu vien » hieu hien, hieu viec, hieu tieng
so sach » so sanh, bo sach, co sach
va hanh » van hanh, va thanh, va danh
ky sang » ky nang, ky dang, ky tang
hanh di » hanh vi, hanh de, hang di
mai hoi » mai khoi, dai hoi, lai hoi
sach ky » sac ky, sach y, sach ty
cac dau » cac dan, cac du, cac dai
di cua » dai cua, doi cua, de cua
dau va » dau ve, lau va
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: so sach ky sang ((xa hoi) or (mai hoi)). ((hieu vien) or (thieu nien)) cac dau va hanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky sang ((xa hoi) OR (mai hoi)). ((hieu vien) OR (thieu nien)) cac dau va hanh di cua te.
• Adding a wildcard symbol may retrieve word variants: so sach ky sang ((xa hoi) or (mai hoi)). ((hieu vien) or (thieu nien)) cac dau va hanh di cua te*.