Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
te sach » toc sach
hieu ve » hieu va, hieu van
va hanh » van hanh, va danh, ban hanh
su viet » so viet
y nang » ky nang, ly nang, v nang
nang o » nang co, nang ho, nang ro
dai su » dai sua, dai so, dan su
o hoc » co hoc, mo hoc, so hoc
ve am » va am

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 y nang o hoc. hieu ve am thuc ((va hanh) or (va thanh)) dai su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang o hoc. hieu ve am thuc ((va hanh) OR (va thanh)) dai su viet.
• Adding a wildcard symbol may retrieve word variants: te sach y nang o hoc. hieu ve am thuc ((va hanh) or (va thanh)) dai su viet*.