Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
cau theo » cau thi, cau tao
lang ha » long ha
sach ky » sac ky, sach y, sach ty
lang xa » dang xay, lang van
day dan » day danh, dao dan, cay dan
dan tai » van tai, dan thi, han tai
tai cau » tai cac, tai cao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky ((lang xa) or (lang ha)) hoi. ((hieu qua) or (lieu va)) nam thuc day dan tai cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((lang xa) OR (lang ha)) hoi. ((hieu qua) OR (lieu va)) nam thuc day dan tai cau theo.
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((lang xa) or (lang ha)) hoi. ((hieu qua) or (lieu va)) nam thuc day dan tai cau theo*.