Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
thi van » thi lan, thi hanh, thi nang
lua tre » cua tre, luy tre, dua tren
vi lua » vi luu
x hoi » xa hoi, o hoi, x ho

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 ky nang x hoi. ((thien van) OR (thi van)) nam thu ((vat hanh) or (ban hanh)) vi lua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. ((thien van) OR (thi van)) nam thu ((vat hanh) OR (ban hanh)) vi lua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. ((thien van) OR (thi van)) nam thu ((vat hanh) or (ban hanh)) vi lua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. ((thien van) OR (thi van)) nam thu ((vat hanh) or (ban hanh)) vi lua tre*.