Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
phan dau » phan tu, hang dau
phan duc » pham duc, phan tu, tran duc
va hanh » van hanh, va thanh, va danh
sach tu » sach thu, cach tu, sach ty
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
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 tu ((mang xa) or (nang ma)) hoi. hieu van ((phan duc) OR (phan dau)) va hanh vi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu ((mang xa) OR (nang ma)) hoi. hieu van ((phan duc) OR (phan dau)) va hanh vi su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu ((mang xa) or (nang ma)) hoi. hieu van ((phan duc) OR (phan dau)) va hanh vi su tien".
• Adding a wildcard symbol may retrieve word variants: tu sach tu ((mang xa) or (nang ma)) hoi. hieu van ((phan duc) OR (phan dau)) va hanh vi su tien*.