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