Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cau tren » cu tren, dau tren, ca tren
dau vai » dau va, dau hai, dau tai
thuc va » thuc vat, thuc dan, thuc day
toc sac » toc sach, toc san, hoc sach
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
va ngay » tan ngay
sac ky » cac ky, sai ky
va nay » va cay
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 lang xa hoi. hieu ((va nay) OR (va ngay)) thuc va dau vai ((cau tren) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky lang xa hoi. hieu ((va nay) OR (va ngay)) thuc va dau vai ((cau tren) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sac ky lang xa hoi. hieu ((va nay) OR (va ngay)) thuc va dau vai ((cau tren) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: toc sac ky lang xa hoi. hieu ((va nay) OR (va ngay)) thuc va dau vai ((cau tren) or (cua triet))*.