Perhaps you should try some spelling variations:
dang mai » dang hai, dang mau, dang bai
mai khoi » mai khoa, tai khoa, cac khoi
tu sach » thu sach, su sach, te sach
cac ban » cac dan, cac van, can ban
cuc ban » cua ban, cuu ban, duc ban
sach ky » sac ky, sach y, sach ty
hieu va » hieu qua
ky dang » ky nang, ky danh
vi cua » vai cua, di cua
cua te » cua tu

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 ky dang mai khoi. ((hieu va) or (lieu va)) chat ((cuc ban) OR (cac ban)) hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang mai khoi. ((hieu va) OR (lieu va)) chat ((cuc ban) OR (cac ban)) hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang mai khoi. ((hieu va) or (lieu va)) chat ((cuc ban) OR (cac ban)) hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang mai khoi. ((hieu va) or (lieu va)) chat ((cuc ban) OR (cac ban)) hanh vi cua te*.