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