Perhaps you should try some spelling variations:
sach nuoc » sach duoc, cac nuoc, bach tuoc
cau tren » cu tren, dau tren, ca tren
danh tai » dinh tai, hanh tai, anh tai
cua tre » cua te, cuu tre, cua triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
va sach » van sach, va cach, a sach
hieu va » lieu va, hieu qua
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 ((danh tai) or (doanh tai)) ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoi. hieu va sach nuoc va ((danh tai) OR (doanh tai)) ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hoi. hieu va sach nuoc va ((danh tai) or (doanh tai)) ((cua tre) or (cau tren))*.