Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
cua triet » cua viet, su triet, va triet
thanh vi » hanh vi, thanh va, thanh ve
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, dua tren
te sach » toc sach
van bac » van ban, van hac, dan bac
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
van bao » van ban, van dao
bo van » vo van, so van, do van

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