Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
cua tre » cua te, cua triet, dua tren
van cac » van hac, van cau, van bac
cac tuc » cac toc, cac tu, cac tac
nang xa » lang xa, nang ma, mang xa
cuu tre » cau tren, cau treo
tuc va » thuc va, truc va, tuc xa
va dan » ca dan, va dao, va dau
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: su sach y ((nang xa) OR (nang x)) hoi. hieu van cac tuc va dan vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (nang x)) hoi. hieu van cac tuc va dan vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) OR (nang x)) hoi. hieu van cac tuc va dan vi ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) OR (nang x)) hoi. hieu van cac tuc va dan vi ((cua tre) or (cuu tre))*.