Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
cau tren » cu tren, ca tren, cau treo
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cau luc » cau truc, cau phuc
va cau » van cau, va cac, va dau
luc va » duc va, tuc va, loc va
va dao » ca dao
dao vi » dao voi, dao ve, dao va

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 ky nang x ho. hieu va cau luc va dao vi ((cau tren) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang x ho. hieu va cau luc va dao vi ((cau tren) OR (dau tren)).
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x ho. hieu va cau luc va dao vi ((cau tren) or (dau tren))*.