Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
dua tren » dung tren
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
y nang » ly nang, v nang, may nang

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) OR (ky nang)) mai hoi. hieu va cac nuoc va hanh vi ((dua tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (ky nang)) mai hoi. hieu va cac nuoc va hanh vi ((dua tren) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) OR (ky nang)) mai hoi. hieu va cac nuoc va hanh vi ((dua tren) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) OR (ky nang)) mai hoi. hieu va cac nuoc va hanh vi ((dua tren) or (cua tre))*.