Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
hanh dai » hanh tai, hanh dao, vanh dai
hoc sach » hoc sinh, hoc cac, hoc anh
van hanh » van thanh, ban hanh, van anh
xuc van » duc van, luc van, vuc van
cac xuc » cam xuc, cac nuoc, chat xuc
hieu ve » hieu va
tang ma » mang may, tang van
ty tang » tay tang, ty xang, ty hang
ma hoi » mai hoi, xa hoi, ma hoa
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) OR (hoc sach)) ty tang ma hoi. ((hieu ve) or (hieu van)) cac xuc van hanh dai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ty tang ma hoi. ((hieu ve) OR (hieu van)) cac xuc van hanh dai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (hoc sach)) ty tang ma hoi. ((hieu ve) or (hieu van)) cac xuc van hanh dai cua tu".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (hoc sach)) ty tang ma hoi. ((hieu ve) or (hieu van)) cac xuc van hanh dai cua tu*.