Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tinh lam » trinh lam, dinh lam, tinh lao
va triet » va thiet, va trien, ve triet
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
van cau » van dau, van hau, van chat
cau duc » cao duc, cau luc, chu duc
va tinh » may tinh
lam va » nam va, dam va, lam ha
o hoi » co hoi, o hoc, o hai
o lai » o lao

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 lai)). hieu van cau duc va tinh lam va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((o hoi) OR (o lai)). hieu van cau duc va tinh lam va triet.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((o hoi) or (o lai)). hieu van cau duc va tinh lam va triet*.