Perhaps you should try some spelling variations:
doc sach » toc sach, nuoc sach, dac sac
va trien » va truyen, va thiet, va tuyen
hoc sach » hoc sinh, hoc cac, hoc anh
mai hoi » mai khoi, dai hoi, mai doi
hieu ve » hieu va, hieu van
va danh » va dinh, va dan, va hanh
danh ki » danh di, danh kien, danh gia
lai hoi » dai hoi, lai hoa, lai roi
ve cam » ve cham, ve cac, va cam
xuc va » duc va, tuc va, luc va
ki va » khi va, ke va, bi va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc sach) OR (hoc sach)) ky nang ((mai hoi) or (lai hoi)). hieu ve cam xuc va danh ki va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc sach) OR (hoc sach)) ky nang ((mai hoi) OR (lai hoi)). hieu ve cam xuc va danh ki va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc sach) OR (hoc sach)) ky nang ((mai hoi) or (lai hoi)). hieu ve cam xuc va danh ki va trien".
• Adding a wildcard symbol may retrieve word variants: ((doc sach) OR (hoc sach)) ky nang ((mai hoi) or (lai hoi)). hieu ve cam xuc va danh ki va trien*.