Perhaps you should try some spelling variations:
cac khoi » cac thoi, cac khoan, cach thoi
te sach » toc sach
hieu va » lieu va, hieu qua
va hang » van hang, va nang, va lang
hieu ve » hieu van
cau luc » cau truc, cau phuc
va cua » va chua, via cua, ca cua
luc va » duc va, tuc va, loc va
cua su » qua su
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang ((ma hoi) or (cac khoi)). ((hieu ve) or (hieu va)) cau luc va hang va cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ((ma hoi) OR (cac khoi)). ((hieu ve) OR (hieu va)) cau luc va hang va cua su.
• Adding a wildcard symbol may retrieve word variants: te sach y nang ((ma hoi) or (cac khoi)). ((hieu ve) or (hieu va)) cau luc va hang va cua su*.