Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
van hanh » van thanh, ban hanh, van anh
cham tuc » nham thuc, pham thuc, tham thuc
te sach » toc sach
va cham » va chat, va tham
tuc van » thuc van, truc van, tuc va
hieu va » lieu va, hieu qua
ty nang » ky nang, ty xang, ty hang
di cua » doi cua, de cua, do cua
x hoi » xa hoi, o hoi, x ho

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) OR (hoc sach)) ty nang x hoi. hieu va cham tuc van hanh ((di cua) OR (dai cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (hoc sach)) ty nang x hoi. hieu va cham tuc van hanh ((di cua) OR (dai cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (hoc sach)) ty nang x hoi. hieu va cham tuc van hanh ((di cua) OR (dai cua)) tre*.