Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
te sach » toc sach
hanh va » hang va, hanh vi
sach ky » sac ky, sach y, sach ty
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
su tien » su kien, su hien, tu tieng
tam tu » nam tu, dam tu, tam thuc
cam tu » cam thu, nam tu, dam tu

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