Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
truc ban » thuc ban, truc dan, truc van
sach ty » sach y, sach tu, sach thu
cuu tre » cua tre, cau treo
hanh di » hanh vi, hanh de, hang di
su sach » so sach, vu sach
tuc ban » thuc ban, tu ban, tuc dan
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
va dau » va dao

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 ty nang xa hoi. lieu va dau ((tuc ban) OR (truc ban)) hanh di ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang xa hoi. lieu va dau ((tuc ban) OR (truc ban)) hanh di ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang xa hoi. lieu va dau ((tuc ban) OR (truc ban)) hanh di ((cuu tre) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang xa hoi. lieu va dau ((tuc ban) OR (truc ban)) hanh di ((cuu tre) or (cau tren))*.