Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
danh gia » dan gian
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
su tien » su kien, su hien, tu tieng
ve cac » va cac, vien cac
dac va » day va, dat va, dai va
gia su » gia suc, giao su, gia sa

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky nang xa hoi. hieu ve cac ((dac va) or (duc va)) danh gia su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. hieu ve cac ((dac va) OR (duc va)) danh gia su tien.
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu ve cac ((dac va) or (duc va)) danh gia su tien*.