Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
van tham » van thanh, van tuan, van chat
hieu van » hieu va, thien van, lieu va
sach dao » lanh dao
sach lo » sach doi, sach hoi, sach moi
tham oc » tham nuoc, cham soc, tham hoa
lai cua » hai cua, lai chau, thai cua
oc van » hoc van, luoc van, quoc van
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: toc ((sach lo) OR (sach dao)) nang x hoi. hieu van tham oc van hanh ((lai cua) OR (dai cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach lo) OR (sach dao)) nang x hoi. hieu van tham oc van hanh ((lai cua) or (dai cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: toc ((sach lo) OR (sach dao)) nang x hoi. hieu van tham oc van hanh ((lai cua) or (dai cua)) tre*.