Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
qua cac » cua cac
cac duc » cac du, cao duc, cac dac
y nang » ky nang, ly nang, v nang
va dan » ca dan, va dao, va dap
va dau » va dao
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) or (thuoc sach)) y nang xa hoi. hieu qua cac duc ((va dan) or (va dau)) va cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) y nang xa hoi. hieu qua cac duc ((va dan) OR (va dau)) va cua viet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuoc sach)) y nang xa hoi. hieu qua cac duc ((va dan) or (va dau)) va cua viet*.