Perhaps you should try some spelling variations:
hieu luan » hieu luat, hieu quan, tieu luan
luan phan » luan van, luan hoan
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
phan duc » pham duc, phan tu, phan dau
sach ky » sach y, sach ty, sach kem
duc van » duc va, duc tan, duc manh
mang xa » lang xa, mang may, dang xay
nang ma » tang ma, sang ma, nang cao
sac ky » cac ky, sai ky
vi su » va su, ve su, ki su

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