Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hang tai » hang va, dung tai
va hang » van hang, va nang, va lang
nang ma » tang ma, sang ma, mang may
cua tre » cuu tre, cua triet, dua tren
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
ve cac » va cac, vien cac
cac lo » cac lop, cac co, cac bo
cua te » cua tu
lo va » lo van, lao va, ly va

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 ky ((nang ma) OR (nang cao)) hoi. hieu ve cac lo va hang tai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang ma) OR (nang cao)) hoi. hieu ve cac lo va hang tai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang ma) OR (nang cao)) hoi. hieu ve cac lo va hang tai ((cua tre) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang ma) OR (nang cao)) hoi. hieu ve cac lo va hang tai ((cua tre) or (cua te))*.