Perhaps you should try some spelling variations:
hac truc » hoc truc, hang truc, sach truc
va triet » va thiet, va trien, ve triet
so sach » so sanh, bo sach, hoc sach
co sach » bo sach, cuon sach, hoc sach
hieu va » hieu qua
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho
vi va » vi van, vai va, vu va

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