Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
nam tuc » nam thuc, nam truc, nam thuoc
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky
nam tu » nam thu, nam thuc

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sac ky) or (sai ky)) tang ma hoi. hieu van ((nam tuc) OR (nam tu)) va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sai ky)) tang ma hoi. hieu van ((nam tuc) OR (nam tu)) va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sac ky) or (sai ky)) tang ma hoi. hieu van ((nam tuc) OR (nam tu)) va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (sai ky)) tang ma hoi. hieu van ((nam tuc) OR (nam tu)) va hanh vai cua tre*.