Perhaps you should try some spelling variations:
dua tren » dung tren
cuu tre » cua tre, cau tren, cau treo
hanh ca » hanh cac, hanh cat, hanh cua
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, te sach, tu cach
nang ma » tang ma, sang ma, nang cao
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
ma hoi » mai hoi, xa hoi, ma hoa
cac tu » cac thu, cach tu, cac du

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