Perhaps you should try some spelling variations:
quoc ban » quoc bao, quoc lan, quoc quan
ban hanh » ban hang
hanh vai » hanh vi, hanh va, hanh tai
cua viet » ca viet, hoa viet, cua vat
te sach » toc sach
nang xa » nang x, lang xa, nang ma
vai cua » dai cua, hai cua, lai cua
ve cac » vien cac

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) or (vu bach)) ky nang xa hoi. hieu ((ve cac) OR (va cac)) quoc ban hanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (vu bach)) ky nang xa hoi. hieu ((ve cac) OR (va cac)) quoc ban hanh vai cua viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (vu bach)) ky nang xa hoi. hieu ((ve cac) OR (va cac)) quoc ban hanh vai cua viet*".