Perhaps you should try some spelling variations:
vien dai » hien dai
vien cac » vien bach, vien da, gian cac
cua tre » cua te, cua triet, dua tren
hang di » hang doi, hang vi, hang dien
va hang » van hang, va nang, va lang
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cuu tre » cau tren, cau treo

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 ky lang xa hoi. hieu ((vien cac) OR (vien dai)) thuc va hang di ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang xa hoi. hieu ((vien cac) OR (vien dai)) thuc va hang di ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang xa hoi. hieu ((vien cac) OR (vien dai)) thuc va hang di ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang xa hoi. hieu ((vien cac) OR (vien dai)) thuc va hang di ((cua tre) or (cuu tre))*.