Perhaps you should try some spelling variations:
nang lai » nang tai, mang lai, nang cai
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach vu » sach va, sach tu, sach uu
su tien » su kien, tu tieng, dau tien
hanh ki » hanh vi, hanh ky, hanh kien
duc van » duc va, duc tan, duc manh
hieu va » hieu qua
lai hoi » dai hoi, lai hoa, lai roi
vu nang » vuc nang, va nang, vu dang
su hien » su kien, thu hien, nhu hien

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 vu nang lai hoi. ((hieu va) OR (lieu va)) pham duc van hanh ki ((su tien) or (su hien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang lai hoi. ((hieu va) OR (lieu va)) pham duc van hanh ki ((su tien) OR (su hien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang lai hoi. ((hieu va) OR (lieu va)) pham duc van hanh ki ((su tien) or (su hien))".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang lai hoi. ((hieu va) OR (lieu va)) pham duc van hanh ki ((su tien) or (su hien))*.