Perhaps you should try some spelling variations:
chat truc » cau truc
hieu van » hieu va, thien van, lieu va
danh dai » danh dau, danh di, danh sai
chat xuc » chat huu, cam xuc, chao xu
va danh » va dinh, va dan, va hanh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoc » co hoc, cho hoc, chat hoc
cao hoi » cau hoi, co hoi, tao hoi
cua tre » cua te, cuu tre, cua triet

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