Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, dua tren
nang o » nang co, nang ho, nang ro
cac bo » bac bo
cac co » cac cong
o hai » co hai, so hai, o lai

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 ty nang o hai. lieu va ((cac bo) or (cac co)) van hanh vi ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang o hai. lieu va ((cac bo) OR (cac co)) van hanh vi ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang o hai. lieu va ((cac bo) or (cac co)) van hanh vi ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: te sach ty nang o hai. lieu va ((cac bo) or (cac co)) van hanh vi ((cua tre) OR (cua triet))*.