Perhaps you should try some spelling variations:
chet nuoc » chet duoc, che duoc, chua nuoc
va thanh » gia thanh, ban thanh, va tinh
thanh va » thanh van, hanh va, thanh ha
va triet » va thiet, va trien, ve triet
so sach » so sanh, bo sach, co sach
te sach » toc sach
hieu va » lieu va, hieu qua
va chet » va chiet, va che, va chat
x hoi » o hoi, x ho, 5 hoi
va va » va van, va vua, va vai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (te sach)) ky nang ((x hoi) OR (xa hoi)). hieu va chet nuoc va thanh va va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (te sach)) ky nang ((x hoi) OR (xa hoi)). hieu va chet nuoc va thanh va va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) or (te sach)) ky nang ((x hoi) OR (xa hoi)). hieu va chet nuoc va thanh va va triet".
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (te sach)) ky nang ((x hoi) OR (xa hoi)). hieu va chet nuoc va thanh va va triet*.