Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
van thanh » ban thanh
van tuan » van quan, van ban, anh tuan
vien cac » vien bach, vien dai, vien da
su triet » su viet, su tien, ve triet
cac duc » cac du, cao duc, cac dac
mai hoi » mai khoi, dai hoi, lai hoi
tu sach » thu sach, su sach, te sach
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach v nang ((mai hoi) or (xa hoi)). hieu vien cac duc ((van thanh) OR (van tuan)) lai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v nang ((mai hoi) OR (xa hoi)). hieu vien cac duc ((van thanh) OR (van tuan)) lai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v nang ((mai hoi) or (xa hoi)). hieu vien cac duc ((van thanh) OR (van tuan)) lai su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach v nang ((mai hoi) or (xa hoi)). hieu vien cac duc ((van thanh) OR (van tuan)) lai su triet*.