Perhaps you should try some spelling variations:
ban hanh » ban hang
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, van bac
van hai » van ha, van chat, van hanh
va hanh » van hanh, va thanh, va danh
vi cau » va cau, ve cau, di cau
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. hieu ((van cac) or (van hai)) xuc ((va hanh) or (ban hanh)) vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu ((van cac) OR (van hai)) xuc ((va hanh) OR (ban hanh)) vi cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu ((van cac) or (van hai)) xuc ((va hanh) or (ban hanh)) vi cau tren*.