Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
va hanh » van hanh, va thanh, va danh
cam duc » cam xuc, cao duc, pham duc
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky
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) OR (sai ky)) nang ma 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) OR (sai ky)) nang ma hoi. hieu va cam duc va hanh vi ((cua te) or (va trien))~".
• Adding a wildcard symbol may retrieve word variants: doc ((sac ky) OR (sai ky)) nang ma hoi. hieu va cam duc va hanh vi ((cua te) or (va trien))*.