Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cau luc » cau truc, cau phuc
cu tren » tu tren, dua tren
va cau » van cau, va cac, va cao
ca dan » cac dan, ca dao
va dau » va dao

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 sach ky nang x ho. hieu va cau luc ((ca dan) OR (va dau)) vi ((cu tren) OR (dau tren))~.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x ho. hieu va cau luc ((ca dan) or (va dau)) vi ((cu tren) or (dau tren))*.