Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
tu sach » su sach, te sach, tu cach
van cuu » van cau, van chu, van cu
dac ban » cac ban, dac san, duc ban
hai cua » thai cua, hoi cua, lai cua
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 cuu dac ban thanh ((hai cua) or (dai 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 cuu dac ban thanh ((hai cua) OR (dai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) y nang x hoi. hieu van cuu dac ban thanh ((hai cua) or (dai cua)) tre*.