Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
lap lai » lap tai, lay lai, lam lai
cac luc » cau luc, coc luc, cac nuoc
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
lap hai » lap tai, lap hoat, lanh hai
ky sang » ky nang, ky dang, ky tang
ve cac » va cac, vien cac
luc va » duc va, tuc va, loc va
dan vi » doan vi, dan va, gan vi
cua te » cua tu

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 ky sang ((lap hai) or (lap lai)). hieu ve cac luc va ((dan vi) OR (don vi)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky sang ((lap hai) OR (lap lai)). hieu ve cac luc va ((dan vi) OR (don vi)) cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky sang ((lap hai) or (lap lai)). hieu ve cac luc va ((dan vi) OR (don vi)) cua te*".