Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
ty nang » ty xang, ty hang, ly nang
hieu va » lieu va, hieu qua
cao tuc » dao tuc, cao duc, cao suc
va vanh » va van, va danh, va hanh
tai cau » tai cac
tai cao » thai cao, tao cao, tai sao
va cao » va cac, va co, va dao
tuc va » thuc va, truc va, tuc xa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ky nang)) xa hoi. hieu va cao tuc va vanh ((tai cau) OR (tai cao)) trieu~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) OR (ky nang)) xa hoi. hieu va cao tuc va vanh ((tai cau) or (tai cao)) trieu~".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) OR (ky nang)) xa hoi. hieu va cao tuc va vanh ((tai cau) or (tai cao)) trieu*.