Perhaps you should try some spelling variations:
toan tap » toan ban
van chat » cao chat
hang tai » hang va, dung tai
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
so viet » hoc viet
luc va » tuc va, loc va
tai so » tai sao, dai so, tai co

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang xa hoi. hieu ((toan tap) OR (van chat)) ((luc va) OR (duc va)) hang tai so viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang xa hoi. hieu ((toan tap) or (van chat)) ((luc va) OR (duc va)) hang tai so viet~".
• Adding a wildcard symbol may retrieve word variants: te sach ty nang xa hoi. hieu ((toan tap) or (van chat)) ((luc va) OR (duc va)) hang tai so viet*.