Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
van hanh » van thanh, ban hanh, van anh
cham luc » cham soc, nhan luc, cham cuu
hanh le » thanh le, hanh ve, hanh de
luc van » luoc van, luu van, duc van
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
cua tre » cua te, cuu tre, cua triet
ma hoi » xa hoi, ma hoa, me hoi
le cua » ly cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) OR (doc sach)) ky nang ((ma hoi) or (mai hoi)). hieu ve cham luc van hanh le cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky nang ((ma hoi) OR (mai hoi)). hieu ve cham luc van hanh le cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) ky nang ((ma hoi) or (mai hoi)). hieu ve cham luc van hanh le cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) ky nang ((ma hoi) or (mai hoi)). hieu ve cham luc van hanh le cua tre*.