Perhaps you should try some spelling variations:
hoa hoi » khoa hoi, hoa hoc, hoa doi
tai cua » thai cua, tai cuc, tri cua
cac tuc » cac toc, cac tu, cac tac
sach ky » sac ky, sach y, sach ty
so sach » so sanh, bo sach, co sach
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
ha hoi » ha noi, xa hoi, va hoi
xa dan » xa dai, va dan, ma dan
ca dan » cac dan, ca dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky dang ((ha hoi) or (hoa hoi)). lieu va cac tuc ((xa dan) or (ca dan)) tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky dang ((ha hoi) OR (hoa hoi)). lieu va cac tuc ((xa dan) OR (ca dan)) tai cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach ky dang ((ha hoi) or (hoa hoi)). lieu va cac tuc ((xa dan) or (ca dan)) tai cua tre*.