Perhaps you should try some spelling variations:
sach thien » sach thieu, sach tien, cach thien
cau treo » cau theo, cau tren, cau triet
cau thuc » cau truc, cuu thuc, can thuc
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
thuc va » thuc vat, thuc dan, thuc day
so sach » so sanh, bo sach, co sach
bang va » ban 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 sach thien ((bang va) or (hang va)) hoi. hieu van cau thuc va dinh vi ((dua tren) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach thien ((bang va) OR (hang va)) hoi. hieu van cau thuc va dinh vi ((dua tren) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: so sach thien ((bang va) or (hang va)) hoi. hieu van cau thuc va dinh vi ((dua tren) or (cau treo))*.