Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
su sach » vu sach
san cua » sang cua, ban cua, dan cua
dua ban » dia ban, cua ban, qua ban
va chay » va chat, va cham, va chan
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet
va cay » va cac, va cao, va cai

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