Perhaps you should try some spelling variations:
thanh dai » thanh tai, thanh dat, thanh oai
thanh hai » thanh phan, thanh hoa, thanh san
cua tre » cua te, cuu tre, cua triet
tang ma » tang van
hieu ve » hieu va, hieu van
cam duc » cam xuc, cao duc, pham duc
duc ban » duc tan, duc van, dua ban
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky
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 sac ky ((tang ma) OR (mang may)) hoi. hieu ve cam duc ban ((thanh dai) or (thanh hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky ((tang ma) OR (mang may)) hoi. hieu ve cam duc ban ((thanh dai) OR (thanh hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky ((tang ma) OR (mang may)) hoi. hieu ve cam duc ban ((thanh dai) or (thanh hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sac ky ((tang ma) OR (mang may)) hoi. hieu ve cam duc ban ((thanh dai) or (thanh hai)) cua tre*.