Perhaps you should try some spelling variations:
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
cam tuc » cam xuc, cam tu, nam thuc
va hanh » van hanh, va thanh, va danh
tu cao » cu cao, tu cac, vu cao
ma hoi » xa hoi, ma hoa, me hoi
ve cam » ve cham, ve cac, va cam
tuc va » thuc va, truc va, tuc xa

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 cao ky nang ((ma hoi) OR (mai hoi)). hieu ve cam tuc va hanh vi ((cau tren) OR (dau tren))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cao ky nang ((ma hoi) or (mai hoi)). hieu ve cam tuc va hanh vi ((cau tren) OR (dau tren))~".
• Adding a wildcard symbol may retrieve word variants: tu cao ky nang ((ma hoi) or (mai hoi)). hieu ve cam tuc va hanh vi ((cau tren) OR (dau tren))*.