Perhaps you should try some spelling variations:
dang xay » dang van, van xay
cac thuc » cach thuc, cac thu, can thuc
thuc van » thuc vat, thuc dan, thuc va
van luan » van quan, van tuan, von luan
dau tren » dau tien, dat tren, dau tieng
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
luan vi » quan vi, luan va, luan ve
ve cac » va cac, vien cac
vi dau » vi dai, va dau, bi dau

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) or (dang xay)) hoi. hieu ve cac thuc van luan vi dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty ((xang xa) OR (dang xay)) hoi. hieu ve cac thuc van luan vi dau tren.
• Adding a wildcard symbol may retrieve word variants: te sach ty ((xang xa) or (dang xay)) hoi. hieu ve cac thuc van luan vi dau tren*.