Perhaps you should try some spelling variations:
khong thong » thong thong, khong trong, thong thuong
hieu lang » chieu sang, hieu quang, nhieu tang
thong dan » thong van, tuong dan, thong den
toan cao » toan ban
toan tap » toan ban
ho hieu » ho chieu, hoi hieu, nho hieu
hang ca » nang cao, hang tai, hang dau

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: ho hieu lang - nhanh ((hang ca) OR (hang va)) khong thong dan ((toan cao) OR (toan tap))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - nhanh ((hang ca) or (hang va)) khong thong dan ((toan cao) OR (toan tap))~".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - nhanh ((hang ca) or (hang va)) khong thong dan ((toan cao) OR (toan tap))*.