Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
sach thu » sach thue, sach thieu, sach tham
cuu tre » cua tre, cau treo
dau thi » cau thi, dan thi, dao thi
cac xuc » cam xuc, cac nuoc, chat xuc
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, luc va
va dau » va dao
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 ((sac ky) or (sach thu)) nang x hoi. lieu va cac xuc va dau thi ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sach thu)) nang x hoi. lieu va cac xuc va dau thi ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sac ky) or (sach thu)) nang x hoi. lieu va cac xuc va dau thi ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (sach thu)) nang x hoi. lieu va cac xuc va dau thi ((cuu tre) OR (cau tren))*.