Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
ban thuc » ban thuoc, dan thuc, van thuc
thuc van » thuc vat, thuc dan, thuc va
dua tren » dung tren
cau treo » cau theo, cau tren, cau triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
van dan » ban dan, van dao, van 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 ky nang xa hoi. hieu van ban thuc van dan vi ((dua tren) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. hieu van ban thuc van dan vi ((dua tren) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. hieu van ban thuc van dan vi ((dua tren) or (cau treo))*.