Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
cam thuc » am thuc, cam thu, can thuc
mai khoi » mai khoa, tai khoa, cac khoi
day hanh » day nhanh, day thanh, dao hanh
nam thuc » nam thuoc, am thuc, nam thu
hieu ve » hieu va, hieu van
dai hoi » dai hoc, dai hai, dai moi
cam ky » cao ky, cac ky
vi cau » va cau, ve cau, di cau
tu cam » tu cham, tu cac, tu nam

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu cam ky nang ((mai khoi) OR (dai hoi)). hieu ve ((cam thuc) OR (nam thuc)) day hanh vi cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cam ky nang ((mai khoi) or (dai hoi)). hieu ve ((cam thuc) OR (nam thuc)) day hanh vi cau tren~".
• Adding a wildcard symbol may retrieve word variants: tu cam ky nang ((mai khoi) or (dai hoi)). hieu ve ((cam thuc) OR (nam thuc)) day hanh vi cau tren*.