Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
tham duc » pham duc, tham du, than duc
tu sach » thu sach, su sach, te sach
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va thanh, va danh
va tham » van tham, va cham, va thanh
hieu va » lieu va, hieu qua
ca tren » cau tren, cu tren, la tren
nang o » nang co, nang ho, nang ro
y nang » ky nang, ly nang, v nang
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: ((tu sach) or (thuoc sach)) y nang o hoi. hieu va tham duc va hanh vi ((cua tre) or (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) y nang o hoi. hieu va tham duc va hanh vi ((cua tre) OR (ca tren)).
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuoc sach)) y nang o hoi. hieu va tham duc va hanh vi ((cua tre) or (ca tren))*.