Perhaps you should try some spelling variations:
chat triet » chet triet, phat trien, chat thien
thanh lam » thanh lap, hanh lam, thanh nam
van thanh » ban thanh, van tuan
lam chat » luan chat, cao chat, ly chat
hieu van » hieu va, thien van, lieu va
duc van » duc va, duc tan, duc manh
cau duc » cao duc, cau luc, chu duc
van cau » van dau, van hau, van chat
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
o hoa » do hoa, so hoa, o ha
o hoi » co hoi, o hoc
o hai » co hai, so hai, o lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty nang ((((o hoi) or (o hoa))) or (o hai)). hieu van cau duc van thanh lam chat triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((((o hoi) OR (o hoa))) OR (o hai)). hieu van cau duc van thanh lam chat triet.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((((o hoi) or (o hoa))) or (o hai)). hieu van cau duc van thanh lam chat triet*.