Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
vien cac » vien bach, vien dai, vien da
dao minh » cao minh, van minh, duc minh
cuu tre » cua tre, cau treo
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
va dao » ca dao
ve cac » va cac
su va » su van, tu va
x hoi » xa hoi, o hoi, x ho

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 ky nang x hoi. hieu ((ve cac) or (vien cac)) su va dao minh ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu ((ve cac) OR (vien cac)) su va dao minh ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. hieu ((ve cac) or (vien cac)) su va dao minh ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu ((ve cac) or (vien cac)) su va dao minh ((cuu tre) OR (cau tren))*.