Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
sinh cua » manh cua, dinh cuu, sinh va
vat hanh » vat thanh, van hanh, nhat hanh
cam thuc » am thuc, nam thuc, cam thu
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
van cam » van nam, van lam, van cau
tang o » trang o, lang o
xang o » lang o, dang o

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach tu ((xang o) or (tang o)) hoi. hieu van cam thuc ((vat hanh) OR (va hanh)) sinh cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu ((xang o) OR (tang o)) hoi. hieu van cam thuc ((vat hanh) OR (va hanh)) sinh cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu ((xang o) or (tang o)) hoi. hieu van cam thuc ((vat hanh) OR (va hanh)) sinh cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach tu ((xang o) or (tang o)) hoi. hieu van cam thuc ((vat hanh) OR (va hanh)) sinh cua viet*.