Perhaps you should try some spelling variations:
cham luc » cham soc, nhan luc, cham cuu
mai duoc » mai quoc, mai duc, mat duoc
tai duoc » tao duoc, tan duoc, ta duoc
va hang » van hang, va nang, va lang
bo sach » co sach, hoc sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
dai hoi » dai hoc, dai hai, dai moi
mai doi » moi doi, mai hoi, mai khoi
ve cham » va cham, ve chat, vu cham
luc va » duc va, tuc va, loc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach ky nang ((mai doi) or (dai hoi)). hieu ve cham luc va hang ((tai duoc) OR (mai duoc)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach ky nang ((mai doi) OR (dai hoi)). hieu ve cham luc va hang ((tai duoc) OR (mai duoc)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "bo sach ky nang ((mai doi) or (dai hoi)). hieu ve cham luc va hang ((tai duoc) OR (mai duoc)) tren".
• Adding a wildcard symbol may retrieve word variants: bo sach ky nang ((mai doi) or (dai hoi)). hieu ve cham luc va hang ((tai duoc) OR (mai duoc)) tren*.