Perhaps you should try some spelling variations:
co sach » bo sach, cuon sach, hoc sach
hieu va » lieu va, hieu qua
hang di » hang doi, hang vi, hang dien
va hang » van hang, va nang, va lang
cao suc » cao su, cao duc
sach ty » sach y, sach tu, sach thu
cua tuc » cua duc, cua thuoc, luat tuc
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
suc va » duc va, tuc va, luc va
cua tu » cua su, cua cu, cua te

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

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