Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
minh cau » minh chau, sinh cau, minh can
dao minh » cao minh, van minh, duc minh
vien cac » vien bach, vien dai, vien da
tu sach » thu sach, su sach, te sach
ve cac » va cac
y nang » ky nang, ly nang, v nang
va dao » ca dao
su va » su van, tu va
5 hoi » o hoi

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 y nang ((5 hoi) or (xa hoi)). hieu ((ve cac) or (vien cac)) su va dao minh cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((5 hoi) OR (xa hoi)). hieu ((ve cac) OR (vien cac)) su va dao minh cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((5 hoi) or (xa hoi)). hieu ((ve cac) or (vien cac)) su va dao minh cau tren*.