Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
thu sach » thuat sach, thuoc sach, thu hoach
va thanh » gia thanh, ban thanh, va tinh
tang mai » tang ma, tang tai, lang mai
vai cua » dai cua, hai cua, lai cua
cham lo » cham o, cham soc, cham hoi
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
tu sach » su sach, te sach, tu cach
cua tre » cua te, cuu tre, cua triet
cam lo » nam lo, cam ly, cam o
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 (tu sach)) y tang mai hoi. hieu ve ((cham lo) or (cam lo)) va thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) y tang mai hoi. hieu ve ((cham lo) OR (cam lo)) va thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (tu sach)) y tang mai hoi. hieu ve ((cham lo) or (cam lo)) va thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (tu sach)) y tang mai hoi. hieu ve ((cham lo) or (cam lo)) va thanh vai cua tre*.