Perhaps you should try some spelling variations:
ban thanh » ban hang
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
cau treo » cau theo, cau tren, cau triet
van cac » van hac, van cau, van bac
cac qua » cau qua, tac quan
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty nang xa hoi. hieu van cac qua ((ban thanh) or (ban hanh)) vai ((cua tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang xa hoi. hieu van cac qua ((ban thanh) OR (ban hanh)) vai ((cua tre) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: su sach ty nang xa hoi. hieu van cac qua ((ban thanh) or (ban hanh)) vai ((cua tre) or (cau treo))*.