Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
qua cau » quan cau, qua cac, qua ca
cau duc » cao duc, cau luc, chu duc
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang
va ban » van ban, va bai, va bao
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((y nang) or (v nang)) xa hoi. hieu qua cau duc va ban va cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (v nang)) xa hoi. hieu qua cau duc va ban va cua viet.
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) or (v nang)) xa hoi. hieu qua cau duc va ban va cua viet*.