Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
ty nang » ky nang, ty xang, ty hang
hieu ve » hieu van
hang di » hang doi, hang vi, hang dien
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
luc va » duc va, tuc va, loc va
di cua » dai cua, doi cua, de cua
suc va » duc va, tuc va, soc va
cua tu » cua tuc, cua su, cua cu
x hoi » xa hoi, o hoi, x ho

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

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