Perhaps you should try some spelling variations:
sach thuat » sach tham, dich thuat, cac thuat
tu sach » thu sach, su sach, te sach
nang xa » lang xa, nang ma, mang xa
hieu vi » hieu voi, hieu va, hieu ve
va hanh » van hanh, va thanh, va danh
bai cua » ban cua, dai cua, bai ca
lai cua » dai cua, hai cua, lai chau
pham » phan

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 thuat ((nang xa) OR (nang x)) hoi. hieu vi pham duc va hanh ((bai cua) or (lai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thuat ((nang xa) OR (nang x)) hoi. hieu vi pham duc va hanh ((bai cua) OR (lai cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thuat ((nang xa) OR (nang x)) hoi. hieu vi pham duc va hanh ((bai cua) or (lai cua)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach thuat ((nang xa) OR (nang x)) hoi. hieu vi pham duc va hanh ((bai cua) or (lai cua)) triet*.