Perhaps you should try some spelling variations:
ban hanh » ban hang
va tinh » may tinh
sach vu » sach va, sach uu, sach xu
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
sach tu » sach thu, cach tu, sach ty
cau tre » cau tren, cau treo, cau tra
di cau » da cau, diem cau

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 vu) OR (sach tu)) nang xa hoi. hieu va cac duc ((ban hanh) or (va tinh)) di cau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach vu) OR (sach tu)) nang xa hoi. hieu va cac duc ((ban hanh) OR (va tinh)) di cau tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach vu) OR (sach tu)) nang xa hoi. hieu va cac duc ((ban hanh) or (va tinh)) di cau tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach vu) OR (sach tu)) nang xa hoi. hieu va cac duc ((ban hanh) or (va tinh)) di cau tre*.