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
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
dau vai » dau va, dau hai, dau tai
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
va nam » van nam, ha nam, va nay
va dau » va dao

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 dang xa hoi. hieu va nam thuc va dau vai ((dau tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky dang xa hoi. hieu va nam thuc va dau vai ((dau tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: toc sac ky dang xa hoi. hieu va nam thuc va dau vai ((dau tren) or (cua tre))*.