Perhaps you should try some spelling variations:
chat soc » cham soc, chat hoc, chat doc
danh sai » dung sai, danh bat, danh dau
danh dai » danh dau, danh di, vanh dai
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
soc va » hoc va, loc va, doc va

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 lang xa hoi. ((hieu van) OR (hieu va)) chat soc va ((danh dai) or (danh sai)) cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang xa hoi. ((hieu van) OR (hieu va)) chat soc va ((danh dai) OR (danh sai)) cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang xa hoi. ((hieu van) OR (hieu va)) chat soc va ((danh dai) or (danh sai)) cua vat".
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang xa hoi. ((hieu van) OR (hieu va)) chat soc va ((danh dai) or (danh sai)) cua vat*.