Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
tinh doi » trinh doc, trinh do, tinh hoc
dang van » hoang van, hang va
tinh oi » tinh toi, tinh voi, tinh vi
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cac tuc » cac toc, cac tu, cac tac
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky ((nang xa) or (dang van)) hoi. hieu va cac tuc va ((tinh oi) OR (tinh doi)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (dang van)) hoi. hieu va cac tuc va ((tinh oi) OR (tinh doi)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (dang van)) hoi. hieu va cac tuc va ((tinh oi) OR (tinh doi)) su triet".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (dang van)) hoi. hieu va cac tuc va ((tinh oi) OR (tinh doi)) su triet*.