Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam tu
van hanh » van thanh, ban hanh, van anh
va triet » va trien, ve triet, cua triet
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
tu sai » tu bai, tu san, tu cai
sai ky » sac ky
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sai ky lang xa hoi. hieu ve ((nam thuc) or (nam thu)) van hanh vi ((va triet) OR (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sai ky lang xa hoi. hieu ve ((nam thuc) OR (nam thu)) van hanh vi ((va triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sai ky lang xa hoi. hieu ve ((nam thuc) or (nam thu)) van hanh vi ((va triet) OR (va thiet))".
• Adding a wildcard symbol may retrieve word variants: tu sai ky lang xa hoi. hieu ve ((nam thuc) or (nam thu)) van hanh vi ((va triet) OR (va thiet))*.