Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
tan hanh » tan thanh, tang hanh, toan hanh
hanh di » hanh vi, hanh de, hang di
sach ly » sach lo, sach ty, sach hay
nang o » nang co, nang ho, nang ro
va cau » van cau, va dau, va cao
di cua » dai cua, doi cua, de cua
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ly) or (sach y)) nang o hoi. hieu ((va cau) or (va cac)) duc tan hanh di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ly) OR (sach y)) nang o hoi. hieu ((va cau) OR (va cac)) duc tan hanh di cua viet.
• Adding a wildcard symbol may retrieve word variants: te ((sach ly) or (sach y)) nang o hoi. hieu ((va cau) or (va cac)) duc tan hanh di cua viet*.