Perhaps you should try some spelling variations:
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
hieu ve » hieu va, hieu van
duoc va » nuoc va, duoc ma, duong va
cua tre » cua te, cuu tre, cua triet
vu sac » vu sach, vu san, va sac
sac ky » cac ky, sai ky
ve dat » de dat, va dat, ve dao
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sac ky ((nang ma) or (tang ma)) hoi. hieu ve dat ((duoc va) OR (duc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sac ky ((nang ma) OR (tang ma)) hoi. hieu ve dat ((duoc va) OR (duc va)) hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sac ky ((nang ma) or (tang ma)) hoi. hieu ve dat ((duoc va) OR (duc va)) hanh vi cua tre*".