Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
chat duc » chat xuc, chat doc, chet duoc
cau tren » dau tren, ca tren, cau treo
thanh vi » hanh vi, thanh va, thanh ve
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, sach thu
duc ban » duc tan, duc van, dua ban
so sach » so sanh, bo sach, co sach
va chat » van chat, va phat, cao chat
hieu va » lieu va, hieu qua
ty nang » ky nang, ty xang, ty hang
cu tren » tu tren, dua tren
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty nang o hoi. hieu va chat duc ban thanh vi ((cua tre) or (((cau tren) OR (cu tren))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty nang o hoi. hieu va chat duc ban thanh vi ((cua tre) OR (((cau tren) OR (cu tren)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty nang o hoi. hieu va chat duc ban thanh vi ((cua tre) or (((cau tren) OR (cu tren))))".
• Adding a wildcard symbol may retrieve word variants: so sach ty nang o hoi. hieu va chat duc ban thanh vi ((cua tre) or (((cau tren) OR (cu tren))))*.