Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
cao duc » dao duc, cao suc, giao duc
cam duc » cam xuc, pham duc, nam duoc
nang xa » lang xa, nang ma, mang xa
sach ky » sac ky, sach y, sach ty
su viet » so viet
vi su » va su, ve su, ki su

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((nang xa) OR (nang x)) hoi. hieu van ((cam duc) OR (cao duc)) van hanh vi su viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((nang xa) or (nang x)) hoi. hieu van ((cam duc) OR (cao duc)) van hanh vi su viet~".
• Adding a wildcard symbol may retrieve word variants: te sach ky ((nang xa) or (nang x)) hoi. hieu van ((cam duc) OR (cao duc)) van hanh vi su viet*.