Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
tinh vai » tinh va, tinh hai, tinh bai
hieu va » lieu va, hieu qua
vai cua » dai cua, hai cua, lai cua
va tinh » may tinh
cham lo » cham o, cham soc, cham hoi
hieu ve » hieu van
tang ma » mang may, tang van
cua tre » cua te, cuu tre, cua triet
y tang » ky tang, 6 tang, 7 tang
cam lo » nam lo, cam ly, cam o
ma hoi » mai hoi, xa hoi, ma hoa

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 y tang ma hoi. ((hieu ve) or (hieu va)) ((cham lo) or (cam lo)) va tinh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y tang ma hoi. ((hieu ve) OR (hieu va)) ((cham lo) OR (cam lo)) va tinh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach y tang ma hoi. ((hieu ve) or (hieu va)) ((cham lo) or (cam lo)) va tinh vai cua tre*.