Perhaps you should try some spelling variations:
sach thien » sach thieu, sach tien, cach thien
thien bang » khien bang, thien ban, thien dang
cau treo » cau theo, cau tren, cau triet
dua tren » dung tren
hieu van » hieu va, thien van, lieu va
cau thuc » cau truc, cuu thuc, can thuc
va tinh » may tinh
vu sach » vu bach, su sach, vu khach
van cau » van dau, van hau, van chat
bang xa » lang xa, bang va, mang xa
va dinh » van dinh, va kinh, vu dinh

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach thien bang xa hoi. hieu van cau thuc ((va dinh) OR (va tinh)) vi ((dua tren) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach thien bang xa hoi. hieu van cau thuc ((va dinh) OR (va tinh)) vi ((dua tren) OR (cau treo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach thien bang xa hoi. hieu van cau thuc ((va dinh) OR (va tinh)) vi ((dua tren) or (cau treo))".
• Adding a wildcard symbol may retrieve word variants: vu sach thien bang xa hoi. hieu van cau thuc ((va dinh) OR (va tinh)) vi ((dua tren) or (cau treo))*.