Perhaps you should try some spelling variations:
luan phan » luan van, luan hoan
hieu luan » hieu luat, hieu quan, tieu luan
su triet » su viet, ve triet
phan duc » pham duc, phan tu, phan dau
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
tu sach » thu sach, su sach, te sach
mang xa » lang xa, mang may, dang xay
nang ma » tang ma, sang ma, nang cao
su tien » su kien, su hien, tu tieng

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