Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cac thuc » cach thuc, cac thu, can thuc
va thanh » ban thanh, va tinh, le thanh
dang xay » dang van, van xay
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
loi su » loai su, loi tu, lai 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 thuc ((va thanh) OR (gia thanh)) loi su triet~.
• 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 thuc ((va thanh) OR (gia thanh)) loi su triet.
• 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 thuc ((va thanh) OR (gia thanh)) loi su triet".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (dang xay)) hoi. hieu va cac thuc ((va thanh) OR (gia thanh)) loi su triet*.