Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thanh tai » thanh hai, thanh toan, doanh tai
va thanh » gia thanh, ban thanh, va tinh
cham hoi » cham voi, cham h'roi, pham hoai
tai cua » thai cua, tai cuc, tri cua
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
y tang » ky tang, 6 tang, 5 tang
cam lo » nam lo, cam ly, cam o
7 tang » 6 tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ((y tang) OR (7 tang)) ma hoi. hieu ve ((cham hoi) or (cam lo)) va thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((y tang) OR (7 tang)) ma hoi. hieu ve ((cham hoi) OR (cam lo)) va thanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ((y tang) OR (7 tang)) ma hoi. hieu ve ((cham hoi) or (cam lo)) va thanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ((y tang) OR (7 tang)) ma hoi. hieu ve ((cham hoi) or (cam lo)) va thanh tai cua tre*.