Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
dau thi » cau thi, dan thi, dao thi
thi cuc » tai cuc
cuc tre » duc tre, cua tre, cuu tre
tuc va » thuc va, truc va, duc va

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