Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh dai » hanh tai, hanh dao, vanh dai
cham luc » cham soc, nhan luc, cham cuu
hieu van » hieu va, thien van, lieu va
su triet » su viet, su tien, ve triet
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va
da nang » cam nang, kha nang, cao nang
va hanh » van hanh, va thanh, va danh
luc va » duc va, tuc va, loc va
v nang » va nang, vu nang, van nang
dai su » dai sua, dai so, dan su

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 ((v nang) or (da nang)) cao hoi. ((hieu ve) OR (hieu van)) cham luc va hanh dai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((v nang) OR (da nang)) cao hoi. ((hieu ve) OR (hieu van)) cham luc va hanh dai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((v nang) or (da nang)) cao hoi. ((hieu ve) OR (hieu van)) cham luc va hanh dai su triet".
• Adding a wildcard symbol may retrieve word variants: toc sach ((v nang) or (da nang)) cao hoi. ((hieu ve) OR (hieu van)) cham luc va hanh dai su triet*.