Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hanh vai » hanh vi, hanh va, hanh tai
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
tu sach » su sach, te sach, tu cach
cac duc » cao duc, cac dac, cac nuoc
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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) OR (thu sach)) y nang x hoi. hieu van ((cac duc) or (cac du)) ban hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) y nang x hoi. hieu van ((cac duc) OR (cac du)) ban hanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) y nang x hoi. hieu van ((cac duc) or (cac du)) ban hanh vai cua tre*".