Perhaps you should try some spelling variations:
dang xay » dang van, van xay
va thanh » ban thanh, va tinh, le thanh
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
su tien » su kien, su hien, tu tieng
cac tu » cac thu, cach tu, cac du
doi su » oi su, don su, voi su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y ((nang xa) or (dang xay)) hoi. hieu va cac tu ((va thanh) OR (gia thanh)) doi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (dang xay)) hoi. hieu va cac tu ((va thanh) OR (gia thanh)) doi su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) or (dang xay)) hoi. hieu va cac tu ((va thanh) OR (gia thanh)) doi su tien".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (dang xay)) hoi. hieu va cac tu ((va thanh) OR (gia thanh)) doi su tien*.