Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
dang xay » dang van, van xay
thuc day » thuc dan, thuc vat
day hanh » day nhanh, day thanh, dao hanh
hanh dai » hanh tai, hanh dao, vanh dai
va triet » va thiet, va trien, ve triet
sach ty » sach y, sach tu, sach thu
ty dang » ty xang, ky dang, ty hang
xay hoi » xa hoi, tay hoi, cay phoi
ve chim » va chim, ve cham, ve chinh
dai va » mai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ty dang xay hoi. hieu ((ve chim) or (cao chat)) thuc day hanh dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty dang xay hoi. hieu ((ve chim) OR (cao chat)) thuc day hanh dai va triet.
• Adding a wildcard symbol may retrieve word variants: doc sach ty dang xay hoi. hieu ((ve chim) or (cao chat)) thuc day hanh dai va triet*.