Perhaps you should try some spelling variations:
toan cua » than cua, tan cua, doanh cua
va thanh » ban thanh, va tinh, le thanh
cua tre » cua te, cuu tre, cua triet
lam duc » lam duoc, pham duc, nam duoc
hieu va » lieu va, hieu qua
dang ha » dong ha, dung ha, lang ha
dang xa » dang xay, lang xa, dang va
sac ky » cac ky, sai ky
va lam » van lam, va lap
su sac » su sach, su cac, su xac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky ((dang xa) or (dang ha)) hoi. hieu va lam duc ((va thanh) OR (gia thanh)) toan cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky ((dang xa) OR (dang ha)) hoi. hieu va lam duc ((va thanh) OR (gia thanh)) toan cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky ((dang xa) or (dang ha)) hoi. hieu va lam duc ((va thanh) OR (gia thanh)) toan cua tre".
• Adding a wildcard symbol may retrieve word variants: su sac ky ((dang xa) or (dang ha)) hoi. hieu va lam duc ((va thanh) OR (gia thanh)) toan cua tre*.