Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
dau tren » dau tien, dat tren, dau tieng
toc sac » toc sach, toc san, hoc sach
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
ky lang » ky nang, ky dang, ky tang
va nam » van nam, ha nam, va nay
sac ky » cac ky, sai ky
va dau » va dao
va dan » ca dan, va dao, va dap

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sac ky lang xa hoi. hieu va nam thuc ((va dan) OR (va dau)) vai ((dau tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky lang xa hoi. hieu va nam thuc ((va dan) OR (va dau)) vai ((dau tren) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sac ky lang xa hoi. hieu va nam thuc ((va dan) OR (va dau)) vai ((dau tren) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: toc sac ky lang xa hoi. hieu va nam thuc ((va dan) OR (va dau)) vai ((dau tren) or (cua tre))*.