Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
cau tren » cu tren, ca tren, cau treo
chat duc » chat xuc, chat doc, chet duoc
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
sach ly » sach y, sach lo, sach ty
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
ly nang » ky nang, ly hang, ly vang
te sach » toc sach
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: te sach ly nang o hoi. hieu ve chat duc va hanh vi ((cua tre) or (((cau tren) OR (dau tren))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ly nang o hoi. hieu ve chat duc va hanh vi ((cua tre) OR (((cau tren) OR (dau tren)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ly nang o hoi. hieu ve chat duc va hanh vi ((cua tre) or (((cau tren) OR (dau tren))))".
• Adding a wildcard symbol may retrieve word variants: te sach ly nang o hoi. hieu ve chat duc va hanh vi ((cua tre) or (((cau tren) OR (dau tren))))*.