Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh dao » lanh dao, thanh dat, thanh dam
sau viet » su viet, dau viet, sau biet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky mang » ky nang, ke mang, ky dang
may hoi » may thoi, tay hoi, mai hoi
hieu va » lieu va, hieu qua
cac tru » ca tru, cac tro, cac tu
cac thu » cach thuc, cac thoi
dao sau » tao sau, day sau, dao cau

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 ky mang may hoi. hieu va ((cac tru) or (cac thu)) van hanh dao sau viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky mang may hoi. hieu va ((cac tru) OR (cac thu)) van hanh dao sau viet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky mang may hoi. hieu va ((cac tru) or (cac thu)) van hanh dao sau viet*.