Perhaps you should try some spelling variations:
hieu luan » hieu luat, hieu quan, tieu luan
luan phan » luan van, luan hoan
thu sach » tu sach, thuat sach, thuoc sach
phan duc » pham duc, phan tu, phan dau
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
ve su » va su

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky ((mang may) or (nang ma)) hoi. hieu luan phan duc va hanh ve su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((mang may) OR (nang ma)) hoi. hieu luan phan duc va hanh ve su triet.
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((mang may) or (nang ma)) hoi. hieu luan phan duc va hanh ve su triet*.