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 thiet, va trien, ve triet
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
hieu ve » hieu va, hieu van
tu sac » tu sach, tu cac, tu san
vi va » vi van, vai va, vu va

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

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