Perhaps you should try some spelling variations:
sach van » sach han, bach van, cach van
dua tren » dung tren
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
nam truc » nam truoc, nam thuc, nam trung
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
hieu he » hieu ve, hiem he, hieu le
nang xa » nang x, lang xa, nang ma
sach va » sach xa, sach ha, sach dao
he nam » ha nam, nghe nam

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 van) or (sach va)) nang xa hoi. hieu he nam truc van hanh va ((dua tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach van) OR (sach va)) nang xa hoi. hieu he nam truc van hanh va ((dua tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: su ((sach van) or (sach va)) nang xa hoi. hieu he nam truc van hanh va ((dua tren) or (cua tre))*.