Perhaps you should try some spelling variations:
doan thi » dan thi, doanh tai, hoang thi
vien cac » vien bach, vien dai, gian cac
te sach » toc sach
sach ky » sac ky, sach y, sach ty
vien da » vien dai, hien dai
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
dan vi » doan vi, don vi, dan va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky lang xa hoi. hieu ((vien cac) OR (vien da)) tu va ((dan vi) or (doan thi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky lang xa hoi. hieu ((vien cac) OR (vien da)) tu va ((dan vi) OR (doan thi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky lang xa hoi. hieu ((vien cac) OR (vien da)) tu va ((dan vi) or (doan thi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky lang xa hoi. hieu ((vien cac) OR (vien da)) tu va ((dan vi) or (doan thi)) cua tre*.