Perhaps you should try some spelling variations:
chat thuc » thuat thuc, nhan thuc, chat thai
hieu cac » hieu luc, hieu va, hieu van
dien cua » dieu cua, dien cuc, dien cu
thu sach » tu sach, thuat sach, thuoc sach
hieu cao » chieu cao, hieu ca, kieu cao
sach ky » sac ky, sach y, sach ty
va danh » va dan, va hanh, dia danh
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet
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: thu sach ky nang x hoi. ((hieu cao) or (hieu cac)) chat thuc ((va danh) OR (va dinh)) dien cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang x hoi. ((hieu cao) OR (hieu cac)) chat thuc ((va danh) OR (va dinh)) dien cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang x hoi. ((hieu cao) or (hieu cac)) chat thuc ((va danh) OR (va dinh)) dien cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang x hoi. ((hieu cao) or (hieu cac)) chat thuc ((va danh) OR (va dinh)) dien cua tre*.