Perhaps you should try some spelling variations:
sach kem » hanh kem
hang tai » hang va, dung tai
nang cau » nang cao, hang cau, nang dau
tai cua » thai cua, tai cuc, tri cua
va hang » van hang, va nang, va lang
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
sach ty » sach y, sach tu, sach thu
xuc va » duc va, tuc va, luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach kem) or (sach ty)) nang cau hoi. ((hieu ve) OR (hieu va)) cam xuc va hang tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach kem) OR (sach ty)) nang cau hoi. ((hieu ve) OR (hieu va)) cam xuc va hang tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach kem) or (sach ty)) nang cau hoi. ((hieu ve) OR (hieu va)) cam xuc va hang tai cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach kem) or (sach ty)) nang cau hoi. ((hieu ve) OR (hieu va)) cam xuc va hang tai cua tre*.