Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
van thanh » van tuan
tu sach » thu sach, su sach, te sach
ve cham » va cham, ve chat, vu cham
cham oc » cham soc, cham o, cham hoi
hieu ve » hieu va, hieu van
vu khac » vu kham, vu khanh, bui khac
nang o » nang co, nang ho, nang ro
y nang » ky nang, ly nang, v nang
va cua » va chua, via cua, ca cua
o hoc » co hoc, mo hoc, so hoc

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: ((tu sach) OR (vu khac)) y nang o hoc. hieu ve cham oc ((van thanh) OR (ban thanh)) va cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (vu khac)) y nang o hoc. hieu ve cham oc ((van thanh) OR (ban thanh)) va cua vat~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu khac)) y nang o hoc. hieu ve cham oc ((van thanh) OR (ban thanh)) va cua vat*.