Perhaps you should try some spelling variations:
cau theo » cau thi, cau tao
hieu cao » chieu cao, hieu cac, hieu ca
chat hoc » chat hoa, chat thom, cho hoc
cau tren » cu tren, dau tren, ca tren
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
dan va » doan va, dan ca, ban va
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
dan vi » doan vi, don vi, gan vi

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: tu sac ky tang xa hoi. hieu cao chat hoc va ((dan vi) OR (dan va)) ((cau tren) OR (cau theo))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky tang xa hoi. hieu cao chat hoc va ((dan vi) OR (dan va)) ((cau tren) or (cau theo))~".
• Adding a wildcard symbol may retrieve word variants: tu sac ky tang xa hoi. hieu cao chat hoc va ((dan vi) OR (dan va)) ((cau tren) or (cau theo))*.