Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh tai » thanh tai, hang tai, han tai
tri nang » thi nang, tra nang, tri bang
va hanh » van hanh, va thanh, va danh
cao suc » cao su
cao duc » dao duc, giao duc, tao duoc
te sach » toc sach
hieu va » lieu va, hieu qua
tu nano » truc nano
tai va » thai va, mai va, tri va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((tu nano) or (tri nang)) xa hoi. hieu va ((cao duc) or (cao suc)) va hanh tai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((tu nano) OR (tri nang)) xa hoi. hieu va ((cao duc) OR (cao suc)) va hanh tai va triet.
• Adding a wildcard symbol may retrieve word variants: te sach ((tu nano) or (tri nang)) xa hoi. hieu va ((cao duc) or (cao suc)) va hanh tai va triet*.