Perhaps you should try some spelling variations:
sach tru » sach truc, sach thu, sach tu
tru nang » tra nang, tri nang, truc nano
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cam luc » cam xuc, cau luc
dinh ve » dinh ket, dinh van
ve cam » ve cham, ve cac, va cam
luc va » duc va, tuc va, loc va
o hoc » co hoc, mo hoc, so hoc
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach tru nang ((o hoc) or (xa hoi)). hieu ve cam luc va ((dich vu) or (dinh ve)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tru nang ((o hoc) OR (xa hoi)). hieu ve cam luc va ((dich vu) OR (dinh ve)) va thiet.
• Adding a wildcard symbol may retrieve word variants: tu sach tru nang ((o hoc) or (xa hoi)). hieu ve cam luc va ((dich vu) or (dinh ve)) va thiet*.