Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
va triet » va thiet, va trien, ve triet
te sach » toc sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
va hanh » van hanh, va thanh, va danh
ma hoi » mai hoi, xa hoi, ma hoa
cam tu » cam thu, nam tu, dam tu

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 nang ma hoi. hieu van ((nam thu) or (cam tu)) va hanh tai ((cua triet) OR (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ma hoi. hieu van ((nam thu) OR (cam tu)) va hanh tai ((cua triet) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ma hoi. hieu van ((nam thu) or (cam tu)) va hanh tai ((cua triet) OR (va triet))".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ma hoi. hieu van ((nam thu) or (cam tu)) va hanh tai ((cua triet) OR (va triet))*.