Perhaps you should try some spelling variations:
hieu luan » hieu luat, hieu quan, tieu luan
luan phan » luan van, luan hoan
phan duc » pham duc, phan tu, phan dau
su triet » su viet, su tien, ve triet
mang xa » lang xa, mang may, dang xay
nang ma » tang ma, sang ma, mang may
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky ((mang xa) or (((nang ma) OR (nang cao)))) hoi. hieu luan phan duc va hanh va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((mang xa) OR (((nang ma) OR (nang cao)))) hoi. hieu luan phan duc va hanh va su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((mang xa) or (((nang ma) OR (nang cao)))) hoi. hieu luan phan duc va hanh va su triet".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((mang xa) or (((nang ma) OR (nang cao)))) hoi. hieu luan phan duc va hanh va su triet*.