Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh keo » hanh kem, banh keo, hanh theo
van hanh » van thanh, ban hanh, van anh
cam luoc » cam xuc, tom luoc, dai luoc
keo cua » keo sua, kho cua, khoe cua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
cam lo » nam lo, cam ly, cam o
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) or (toc sach)) ky nang o hoi. hieu ve ((cam luoc) OR (cam lo)) van hanh keo cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang o hoi. hieu ve ((cam luoc) OR (cam lo)) van hanh keo cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky nang o hoi. hieu ve ((cam luoc) OR (cam lo)) van hanh keo cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky nang o hoi. hieu ve ((cam luoc) OR (cam lo)) van hanh keo cua tre*.