Perhaps you should try some spelling variations:
kmay nang » ky nang, kha nang, may nong
van dinh » van minh, van dich, va dinh
may nang » may nong, ky nang, cam nang
va triet » va trien, ve triet, cua triet
tu sach » thu sach, su sach, te sach
dinh vu » dich vu, dinh ve, dinh cu
hieu ve » hieu va, hieu van
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho
thiet » thieu

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 ((may nang) or (kmay nang)) x hoi. hieu ve cac luc van dinh vu ((va triet) OR (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((may nang) OR (kmay nang)) x hoi. hieu ve cac luc van dinh vu ((va triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((may nang) or (kmay nang)) x hoi. hieu ve cac luc van dinh vu ((va triet) OR (va thiet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((may nang) or (kmay nang)) x hoi. hieu ve cac luc van dinh vu ((va triet) OR (va thiet))*.