Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
van hanh » van thanh, ban hanh, van anh
duoc van » duoc va, duc van, duoc ban
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach ty
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, dua tren
hieu ve » hieu va, hieu van
ma hoi » mai hoi, xa hoi, ma hoa
sai ky » sac ky
ve tao » ve bao, de tao, ve tac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ky) or (sai ky)) nang ma hoi. hieu ve tao duoc van hanh di ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sai ky)) nang ma hoi. hieu ve tao duoc van hanh di ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sai ky)) nang ma hoi. hieu ve tao duoc van hanh di ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sai ky)) nang ma hoi. hieu ve tao duoc van hanh di ((cua tre) OR (cua triet))*.