Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thanh dai » thanh hai, thanh tai, thanh dat
thu sach » tu sach, thuoc sach, thu hoach
va thanh » gia thanh, ban thanh, va tinh
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
nam so » nam sao, nam bo
y tang » ky tang, 6 tang, 7 tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) OR (thuat sach)) y tang ma hoi. hieu ve ((cham h'roi) or (nam so)) va thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) y tang ma hoi. hieu ve ((cham h'roi) OR (nam so)) va thanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (thuat sach)) y tang ma hoi. hieu ve ((cham h'roi) or (nam so)) va thanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (thuat sach)) y tang ma hoi. hieu ve ((cham h'roi) or (nam so)) va thanh dai cua tre*.