Perhaps you should try some spelling variations:
hanh dao » lanh dao, thanh dat, thanh dam
te sach » toc 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 tuc » cac toc, cac tu, cac nuoc
cac tac » cac toc, cac bac, cac dac
va hanh » van hanh, va thanh, va danh
su viet » so viet
dao su » dao suu, dan su, cao su

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 mang may hoi. hieu va ((cac tuc) OR (cac tac)) va hanh dao su viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky mang may hoi. hieu va ((cac tuc) OR (cac tac)) va hanh dao su viet".
• Adding a wildcard symbol may retrieve word variants: te sach ky mang may hoi. hieu va ((cac tuc) OR (cac tac)) va hanh dao su viet*.