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
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach ty
mang xa » lang xa, mang may, dang xay
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
tu sach » thu sach, su sach, te sach
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: tu sach ky ((mang xa) or (nang ma)) hoi. hieu luan phan duc ((va hanh) OR (va danh)) vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((mang xa) OR (nang ma)) hoi. hieu luan phan duc ((va hanh) OR (va danh)) vi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((mang xa) or (nang ma)) hoi. hieu luan phan duc ((va hanh) OR (va danh)) vi su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((mang xa) or (nang ma)) hoi. hieu luan phan duc ((va hanh) OR (va danh)) vi su triet*.