Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
chat duc » chat doc, chet duoc, pham duc
van hanh » van thanh, ban hanh, van anh
hieu van » thien van, lieu va, hieu ve
chat xuc » chat huu, cam xuc, chao xu
hanh va » hang va, hanh vi
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
ty nang » ky nang, ty xang, ty hang
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai
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 ty nang o hoi. ((hieu van) or (hieu va)) ((chat duc) or (chat xuc)) van hanh va va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty nang o hoi. ((hieu van) OR (hieu va)) ((chat duc) OR (chat xuc)) van hanh va va triet.
• Adding a wildcard symbol may retrieve word variants: so sach ty nang o hoi. ((hieu van) or (hieu va)) ((chat duc) or (chat xuc)) van hanh va va triet*.