Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
cua viet » ca viet, hoa viet, cua vat
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 » va dao, va dau, va dap
ca dan » cac dan, ca 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: ((thu sach) or (thuoc sach)) y nang xa hoi. hieu qua cac duc ((va dan) OR (ca dan)) va cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) y nang xa hoi. hieu qua cac duc ((va dan) OR (ca dan)) va cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thuoc sach)) y nang xa hoi. hieu qua cac duc ((va dan) OR (ca dan)) va cua viet".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuoc sach)) y nang xa hoi. hieu qua cac duc ((va dan) OR (ca dan)) va cua viet*.