Perhaps you should try some spelling variations:
hoc viet » hoc hien
kho tang » cao tang
van hanh » van thanh, ban hanh, van anh
ky trong » ly trong, ke trong, cay trong
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
ve cam » ve cham, ve cac, va cam
vi hoc » li hoc, va hoc
su sai » su tai, su hai, su dai

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 trong) 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 trong) 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 trong) or (kho tang))) or (ky dang)) mai hoi. hieu ve cam xuc van hanh vi hoc viet*.