Perhaps you should try some spelling variations:
tan hanh » tan thanh, tang hanh, toan hanh
chat doc » chat hoc, chau doc, thuat doc
chat duc » chat xuc, chet duoc, pham duc
cua tre » cua te, cuu tre, cua triet
hanh va » hang va, hanh vi
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
sach ty » sach y, sach tu, sach thu
ma hoi » mai hoi, xa hoi, ma hoa
sai ky » sac ky
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sai ky) or (sach ty)) tang ma hoi. hieu ve ((chat duc) or (chat doc)) tan hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sai ky) OR (sach ty)) tang ma hoi. hieu ve ((chat duc) OR (chat doc)) tan hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: te ((sai ky) or (sach ty)) tang ma hoi. hieu ve ((chat duc) or (chat doc)) tan hanh va cua tre*.