Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
cua triet » cua viet, su triet, va triet
thuc ban » thuoc ban, thuc dan, thu ban
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 » hieu qua
hanh va » hang va

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) OR (lieu va)) nham thuc ban ((hanh va) or (hanh vi)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky mang may hoi. ((hieu va) OR (lieu va)) nham thuc ban ((hanh va) OR (hanh vi)) cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky mang may hoi. ((hieu va) OR (lieu va)) nham thuc ban ((hanh va) or (hanh vi)) cua triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky mang may hoi. ((hieu va) OR (lieu va)) nham thuc ban ((hanh va) or (hanh vi)) cua triet*.