Perhaps you should try some spelling variations:
thanh de » thanh ve, thanh do, thanh le
tu sach » thu sach, su sach, te sach
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
cac tuc » cac toc, cac tu, cac tac
tuc gia » tac gia, duc gia, toc gia
hanh de » hanh ve, hanh kem

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) or (thu hoach)) ky nang cao hoi. hieu va cac tuc gia ((thanh de) OR (hanh de)) hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky nang cao hoi. hieu va cac tuc gia ((thanh de) OR (hanh de)) hoa viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu hoach)) ky nang cao hoi. hieu va cac tuc gia ((thanh de) OR (hanh de)) hoa viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky nang cao hoi. hieu va cac tuc gia ((thanh de) OR (hanh de)) hoa viet*.