Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
doc sac » doc sach, dac sac, hoc sach
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
va hanh » van hanh, va thanh, va danh
sac ky » cac ky, sai ky
ma hoi » mai hoi, ma hoa, me hoi
va cam » va cham, va cac, va cao
cua te » cua tu

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: doc sac ky nang ((ma hoi) OR (xa hoi)). hieu va cam duc va hanh vi ((cua te) OR (va trien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sac ky nang ((ma hoi) OR (xa hoi)). hieu va cam duc va hanh vi ((cua te) or (va trien))~".
• Adding a wildcard symbol may retrieve word variants: doc sac ky nang ((ma hoi) OR (xa hoi)). hieu va cam duc va hanh vi ((cua te) or (va trien))*.