Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
sach ky » sac ky, sach y, sach ty
thuc ca » thuc cua, thuc can, thuc cao
tai cau » tai cac
tai cao » thai cao, tao cao, tai sao
va nam » ha nam, va nay
ca dan » cac dan, ca dao
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ky nang x hoi. hieu ((va nam) or (van nam)) thuc ca dan ((tai cau) OR (tai cao)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky nang x hoi. hieu ((va nam) OR (van nam)) thuc ca dan ((tai cau) OR (tai cao)) treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky nang x hoi. hieu ((va nam) or (van nam)) thuc ca dan ((tai cau) OR (tai cao)) treo".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky nang x hoi. hieu ((va nam) or (van nam)) thuc ca dan ((tai cau) OR (tai cao)) treo*.