Perhaps you should try some spelling variations:
cac trung » cac truong, dac trung, bac trung
trung ca » trung cap, truong ca, trung cua
te sach » toc sach
doan vi » doan va, don vi, doan thi
sach tu » sach thu, cach tu, sach ty
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
dan vi » don vi, dan va, gan vi
ve cac » va cac, vien cac

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 tu ((nang xa) or (lang xa)) hoi. hieu ve cac trung ca ((dan vi) OR (doan vi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach tu ((nang xa) OR (lang xa)) hoi. hieu ve cac trung ca ((dan vi) OR (doan vi)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach tu ((nang xa) or (lang xa)) hoi. hieu ve cac trung ca ((dan vi) OR (doan vi)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: te sach tu ((nang xa) or (lang xa)) hoi. hieu ve cac trung ca ((dan vi) OR (doan vi)) cuu tre*.