Perhaps you should try some spelling variations:
thuc day » thuc dan, thuc vat
dau tren » dau tien, dat tren, dau tieng
toc sac » toc sach, toc san, hoc sach
dan vai » dan va, dan tai, dan vat
cua tre » cua te, cuu tre, cua triet
thuc va » thuc vat, thuc dan
qua nay » qua ngay, qua xay, qua cay
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
sac ky » cac ky, sai ky

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 qua nay ((thuc va) OR (thuc day)) dan 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 qua nay ((thuc va) OR (thuc day)) dan 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 qua nay ((thuc va) OR (thuc day)) dan vai ((dau tren) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: toc sac ky lang xa hoi. hieu qua nay ((thuc va) OR (thuc day)) dan vai ((dau tren) or (cua tre))*.