Perhaps you should try some spelling variations:
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
te sach » toc sach
sach ty » sach y, sach tu, sach thu
doi cua » dai cua, hoi cua
hac duc » hoc duc, ha duc, thach duc
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
va hac » van hac, va khac, va cac
ma hoi » mai hoi, xa hoi, ma hoa
di cua » dai cua, de cua, do cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang ma hoi. hieu va hac duc ((van hanh) OR (ban hanh)) ((di cua) OR (doi cua)) tu~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang ma hoi. hieu va hac duc ((van hanh) or (ban hanh)) ((di cua) OR (doi cua)) tu~".
• Adding a wildcard symbol may retrieve word variants: te sach ty nang ma hoi. hieu va hac duc ((van hanh) or (ban hanh)) ((di cua) OR (doi cua)) tu*.