Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
hieu van » thien van, lieu va, hieu ve
hieu va » lieu va, hieu qua
cuc ban » cua ban, cac ban, cuu ban
nam cuc » nam cac, nam cua, nam thuc
cua tre » cua te, cuu tre, cua triet
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
sac ky » cac ky, sai ky
vi cua » vai cua, di cua

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 ky) or (sac ky)) nang xa hoi. ((hieu van) OR (hieu va)) nam cuc ban thanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sac ky)) nang xa hoi. ((hieu van) OR (hieu va)) nam cuc ban thanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sac ky)) nang xa hoi. ((hieu van) OR (hieu va)) nam cuc ban thanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sac ky)) nang xa hoi. ((hieu van) OR (hieu va)) nam cuc ban thanh vi cua tre*.