Perhaps you should try some spelling variations:
vanh dai » van dai, vanh tai, lanh dao
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
tu sach » thu sach, su sach, te sach
cua tre » cuu tre, cua triet, dua tren
va vanh » va van, va danh, va hanh
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, lang van
va nam » van nam, ha nam, va nay
cua te » cua tu

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