Perhaps you should try some spelling variations:
thieu nien » thien nhien
hieu vien » hieu hien, hieu viec, hieu tieng
hanh dao » lanh dao, thanh dat, thanh dam
hanh dai » hanh tai, vanh dai, thanh dat
cac dai » cac dan, cac bai, can dai
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
ky tang » ky nang, ky dang, kho tang
dai va » mai va
ma hoi » mai hoi, xa hoi, ma hoa
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 tang ma hoi. ((hieu vien) or (thieu nien)) cac dai va ((hanh dai) OR (hanh dao)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky tang ma hoi. ((hieu vien) OR (thieu nien)) cac dai va ((hanh dai) OR (hanh dao)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky tang ma hoi. ((hieu vien) or (thieu nien)) cac dai va ((hanh dai) OR (hanh dao)) cua te".
• Adding a wildcard symbol may retrieve word variants: so sach ky tang ma hoi. ((hieu vien) or (thieu nien)) cac dai va ((hanh dai) OR (hanh dao)) cua te*.