Perhaps you should try some spelling variations:
sach tham » sach nha
chat truc » cau truc, chat xuc
hanh dai » hanh tai, hanh dao, vanh dai
sach thu » sach thue, sach thieu, cach thuc
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
su tien » su kien, su hien, tu tieng
hieu ve » hieu va, hieu van
cao hoi » cau hoi, co hoi, cao hoc
dai su » dai sua, dai so, dan su

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach thu) OR (sach tham)) nang cao hoi. ((hieu ve) or (lieu va)) chat truc va hanh dai su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach thu) OR (sach tham)) nang cao hoi. ((hieu ve) OR (lieu va)) chat truc va hanh dai su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach thu) OR (sach tham)) nang cao hoi. ((hieu ve) or (lieu va)) chat truc va hanh dai su tien".
• Adding a wildcard symbol may retrieve word variants: so ((sach thu) OR (sach tham)) nang cao hoi. ((hieu ve) or (lieu va)) chat truc va hanh dai su tien*.