Perhaps you should try some spelling variations:
vien sach » vien bach, dien sach, kien sach
viet sach » viet anh, dien sach, viet tech
ban hanh » ban hang
va danh » va dinh, va dan, va hanh
bach ky » bac ky
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu bach ky nang xa hoi. hieu ((vien sach) OR (viet sach)) nuoc ((ban hanh) or (va danh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu bach ky nang xa hoi. hieu ((vien sach) OR (viet sach)) nuoc ((ban hanh) OR (va danh)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu bach ky nang xa hoi. hieu ((vien sach) OR (viet sach)) nuoc ((ban hanh) or (va danh)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: vu bach ky nang xa hoi. hieu ((vien sach) OR (viet sach)) nuoc ((ban hanh) or (va danh)) di cua tre*.