Perhaps you should try some spelling variations:
dai hoi » dai hoc, dai hai, dai moi
dai hoa » dai khoa, dai hoc, day hoa
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
cam tu » cam thu, nam tu, dam tu
v nang » va nang, vu nang, van nang
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (vu bach)) v nang xa hoi. hieu ve cam tu va hanh ((dai hoa) or (dai hoi)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu bach)) v nang xa hoi. hieu ve cam tu va hanh ((dai hoa) OR (dai hoi)) viet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu bach)) v nang xa hoi. hieu ve cam tu va hanh ((dai hoa) or (dai hoi)) viet*.