Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
cham giua » tham gia, nhat giua, cam gia
thanh va » thanh van, hanh va, thanh ha
cham dua » chay dua, pham duc, pham duy
te sach » toc sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ky tang » ky nang, ky dang, kho tang
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, va hoi
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 sach ky tang ((ha hoi) or (xa hoi)). hieu ve ((cham dua) OR (cham giua)) ban thanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky tang ((ha hoi) OR (xa hoi)). hieu ve ((cham dua) OR (cham giua)) ban thanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky tang ((ha hoi) or (xa hoi)). hieu ve ((cham dua) OR (cham giua)) ban thanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky tang ((ha hoi) or (xa hoi)). hieu ve ((cham dua) OR (cham giua)) ban thanh va cua tre*.