Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dong cuc » dong luc, dong cua, tong cuc
cao hoi » cau hoi, cao hoc, tao hoi
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
dong cu » dong cua, dong cum, dong co
y nang » ky nang, ly nang, v nang
co hoi » co hoc, co loi
va hoc » van hoc
nuoc » quoc, duoc, ngoc

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 y nang ((cao hoi) or (co hoi)). hieu va hoc nuoc va hanh ((dong cu) OR (dong cuc)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang ((cao hoi) OR (co hoi)). hieu va hoc nuoc va hanh ((dong cu) OR (dong cuc)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y nang ((cao hoi) or (co hoi)). hieu va hoc nuoc va hanh ((dong cu) OR (dong cuc)) triet".
• Adding a wildcard symbol may retrieve word variants: thu sach y nang ((cao hoi) or (co hoi)). hieu va hoc nuoc va hanh ((dong cu) OR (dong cuc)) triet*.