Perhaps you should try some spelling variations:
hoc tien » hoc tieng, hoc hien, hoc tren
hoc vien » hoc hien, hoc viet, hoc tieng
ky tang » ky nang, ky dang, kho tang
tang ma » mang may, tang van
hieu ve » hieu van
hieu va » lieu va, hieu qua
cam tuc » cam xuc, cam tu, nam thuc
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
so sac » so sach, so dac
tuc va » thuc va, truc va, tuc xa
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sac ky tang ma hoi. ((hieu ve) or (hieu va)) cam tuc va dan vi ((hoc vien) or (hoc tien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sac ky tang ma hoi. ((hieu ve) OR (hieu va)) cam tuc va dan vi ((hoc vien) OR (hoc tien)).
• Adding a wildcard symbol may retrieve word variants: so sac ky tang ma hoi. ((hieu ve) or (hieu va)) cam tuc va dan vi ((hoc vien) or (hoc tien))*.