Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cac tuc » cac tu, cac tac, cac nuoc
cac toc » cac toi, cac nuoc, cac thoi
dau thi » cau thi, dan thi, dao thi
cuu tre » cua tre, cau treo
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 ky nang xa hoi. lieu va ((cac tuc) or (cac toc)) va dau thi ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. lieu va ((cac tuc) OR (cac toc)) va dau thi ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. lieu va ((cac tuc) or (cac toc)) va dau thi ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. lieu va ((cac tuc) or (cac toc)) va dau thi ((cuu tre) OR (cau tren))*.