Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
va thanh » gia thanh, va tinh, le thanh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
lai cua » dai cua, hai cua, lai chau
va cam » va cham, va cac, va cao
cua te » cua tu

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 ky sang ((le hoi) or (xa hoi)). hieu va cam duc ((va thanh) OR (ban thanh)) lai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang ((le hoi) OR (xa hoi)). hieu va cam duc ((va thanh) OR (ban thanh)) lai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky sang ((le hoi) or (xa hoi)). hieu va cam duc ((va thanh) OR (ban thanh)) lai cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach ky sang ((le hoi) or (xa hoi)). hieu va cam duc ((va thanh) OR (ban thanh)) lai cua te*.