Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
dau tren » dat tren, dau tieng, dau trong
dau tien » van tien
te sach » toc sach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va luan » vay luan, van luan, va quan
luan vi » quan vi, luan va, luan ve
ve cac » va cac, vien cac

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 ty xang xa hoi. hieu ve cac thuc va luan vi ((dau tren) OR (dau tien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty xang xa hoi. hieu ve cac thuc va luan vi ((dau tren) OR (dau tien))".
• Adding a wildcard symbol may retrieve word variants: te sach ty xang xa hoi. hieu ve cac thuc va luan vi ((dau tren) OR (dau tien))*.