Perhaps you should try some spelling variations:
thanh giau » thanh gian, thanh giang, thanh lieu
van thanh » ban thanh, van tuan
giau cua » gian cua, gia cua, dieu cua
cac lop » cac hop, cac loai
sach ky » sach y, sach ty, sach kem
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
ma hoi » mai hoi, xa hoi, ma hoa
cac lo » cac co, cac bo, cac ho
sac ky » cac ky, sai ky

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

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