Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
suc dang » su dang, nuoc dang, cua dang
tu sach » thu sach, su sach, te sach
tai cuu » tai cuc, tai buu, tai cua
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
o hoc » co hoc, mo hoc, so hoc
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: tu sach ky nang ((x hoi) or (o hoc)). hieu ve cam ((suc dang) OR (suc manh)) thanh tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((x hoi) OR (o hoc)). hieu ve cam ((suc dang) OR (suc manh)) thanh tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((x hoi) or (o hoc)). hieu ve cam ((suc dang) OR (suc manh)) thanh tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) or (o hoc)). hieu ve cam ((suc dang) OR (suc manh)) thanh tai cuu tre*.