Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
dang xay » dang van, van xay
thanh di » thanh doi, thanh de, thanh do
va thanh » gia thanh, ban thanh, va tinh
cac nuoc » cap nuoc, dat nuoc, cua nuoc
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
tang ma » mang may, tang van
su sach » so sach, vu sach
di su » doi su, ki su, da su

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((tang ma) OR (dang xay)) hoi. hieu va ((cac nuoc) OR (hoc nuoc)) va thanh di su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((tang ma) or (dang xay)) hoi. hieu va ((cac nuoc) OR (hoc nuoc)) va thanh di su triet~".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((tang ma) or (dang xay)) hoi. hieu va ((cac nuoc) OR (hoc nuoc)) va thanh di su triet*.