Perhaps you should try some spelling variations:
kho tang » cao tang
van hanh » van thanh, ban hanh, van anh
hoc viet » hoc hien
ky tang » ky nang, ky trong, tay tang
ky dang » ky nang, ky danh
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
xuc van » duc van, luc van, vuc van
su sai » su tai, su hai, su dai
ve cam » ve cham, ve cac, va cam
vi hoc » li hoc, va hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sai ((((ky tang) OR (kho tang))) or (ky dang)) mai hoi. hieu ve cam xuc van hanh vi hoc viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sai ((((ky tang) OR (kho tang))) OR (ky dang)) mai hoi. hieu ve cam xuc van hanh vi hoc viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sai ((((ky tang) OR (kho tang))) or (ky dang)) mai hoi. hieu ve cam xuc van hanh vi hoc viet".
• Adding a wildcard symbol may retrieve word variants: su sai ((((ky tang) OR (kho tang))) or (ky dang)) mai hoi. hieu ve cam xuc van hanh vi hoc viet*.