Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hang » van khang, van hoang, van thang
cham luc » cham soc, nhan luc, cham cuu
hieu va » lieu va, hieu qua
hang ly » huong ly
luc van » luoc van, luu van, duc van
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
mai hoi » mai khoi, dai hoi, lai hoi
y nang » ky nang, ly nang, v nang
ma hoi » xa hoi, ma hoa, me hoi
ly cua » le cua

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 y nang ((ma hoi) or (mai hoi)). ((hieu ve) OR (hieu va)) cham luc van hang ly cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ((ma hoi) OR (mai hoi)). ((hieu ve) OR (hieu va)) cham luc van hang ly cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang ((ma hoi) or (mai hoi)). ((hieu ve) OR (hieu va)) cham luc van hang ly cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ((ma hoi) or (mai hoi)). ((hieu ve) OR (hieu va)) cham luc van hang ly cua tre*.