Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nang mai » nang ma, nang tai, lang mai
van hanh » van thanh, ban hanh, van anh
chat xuc » chat huu, cam xuc, chao xu
va hanh » va thanh, va danh, ban hanh
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va
y nang » ky nang, ly nang, v nang
vai va » mai va, dai va, hai va
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 sach y nang mai hoi. ((hieu ve) OR (hieu van)) chat xuc ((va hanh) or (van hanh)) vai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang mai hoi. ((hieu ve) OR (hieu van)) chat xuc ((va hanh) OR (van hanh)) vai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang mai hoi. ((hieu ve) OR (hieu van)) chat xuc ((va hanh) or (van hanh)) vai va thiet".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang mai hoi. ((hieu ve) OR (hieu van)) chat xuc ((va hanh) or (van hanh)) vai va thiet*.