Perhaps you should try some spelling variations:
cuon sach » duong sach, cuoc cach, co sach
su triet » su viet, su tien, ve triet
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, sach thu
hang di » hang doi, hang vi, hang dien
tuc va » thuc va, truc va, duc va
di su » doi su, ki su, da su

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

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