Perhaps you should try some spelling variations:
thanh oai » thanh hai, thanh tai, thanh toan
thanh van » thanh san, thanh toan, thanh phan
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cua triet, dua tren
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
duc ban » duc tan, duc van, dua ban
cau duc » cao duc, cau luc, chu duc
van cau » van dau, van hau, van chat
nang xa » nang x, lang xa, nang ma
cuu tre » cau tren, cau treo

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 xa hoi. hieu van cau duc ban ((thanh oai) or (thanh van)) ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu van cau duc ban ((thanh oai) OR (thanh van)) ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. hieu van cau duc ban ((thanh oai) or (thanh van)) ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu van cau duc ban ((thanh oai) or (thanh van)) ((cua tre) OR (cuu tre))*.