Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh dam » thanh dam, hanh lam, hanh nam
van hanh » van thanh, ban hanh, van anh
chat vuc » chat xuc, chat va, chat huu
hieu van » thien van, lieu va, hieu ve
hieu va » lieu va, hieu qua
vuc van » duc van, luc van, thuc van
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
dam va » dam van, nam va, dam ha
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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 xang ((x hoi) OR (o hoi)). ((hieu van) or (hieu va)) chat vuc van hanh dam va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty xang ((x hoi) OR (o hoi)). ((hieu van) OR (hieu va)) chat vuc van hanh dam va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty xang ((x hoi) OR (o hoi)). ((hieu van) or (hieu va)) chat vuc van hanh dam va triet".
• Adding a wildcard symbol may retrieve word variants: so sach ty xang ((x hoi) OR (o hoi)). ((hieu van) or (hieu va)) chat vuc van hanh dam va triet*.