Perhaps you should try some spelling variations:
sanh thien » sach thieu, hanh thiet, manh tien
cau treo » cau theo, cau tren, cau triet
dua tren » dung tren
hieu van » hieu va, thien van, lieu va
dinh vi » dinh ve, dinh viet, dinh tri
va dinh » van dinh, va kinh, va tinh
so sanh » do sanh
truc va » thuc va, thuc vat, trung va
bang va » hang va, trang va, dang van
van cau » van dau, van hau, van chat

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

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