Perhaps you should try some spelling variations:
hoc duoc » hoc nuoc, hoa duoc, hoc dung
cua tre » cua te, cua triet, dua tren
tinh di » tinh doi, trinh di, tinh da
va tinh » may tinh
duoc va » nuoc va, duc va, duoc ma
bach ky » bac ky
cuu tre » cau tren, cau treo
hieu ve » hieu va, hieu van
ve hoc » te hoc, va hoc, vi hoc
ma hoi » mai hoi, xa hoi, me hoi

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: vu bach ky nang ((ma hoi) OR (ma hoa)). hieu ve hoc duoc va tinh di ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu bach ky nang ((ma hoi) or (ma hoa)). hieu ve hoc duoc va tinh di ((cua tre) OR (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: vu bach ky nang ((ma hoi) or (ma hoa)). hieu ve hoc duoc va tinh di ((cua tre) OR (cuu tre))*.