Perhaps you should try some spelling variations:
sach nuoc » sach duoc, cac nuoc, bach tuoc
hanh lai » hanh lam, thanh lap, thanh loi
hanh tai » thanh tai, hang tai, han tai
cua tre » cua te, cua triet, dua tren
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
va sach » van sach, va cach, a sach
hieu va » lieu va, hieu qua
cuu tre » cau tren, cau treo
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: tu sach ky nang o hoi. hieu va sach nuoc va ((hanh lai) OR (hanh tai)) ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoi. hieu va sach nuoc va ((hanh lai) OR (hanh tai)) ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hoi. hieu va sach nuoc va ((hanh lai) OR (hanh tai)) ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hoi. hieu va sach nuoc va ((hanh lai) OR (hanh tai)) ((cua tre) or (cuu tre))*.