Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
nam thuc » nam thuoc, am thuc, nam thu
cau theo » cau thi, cau tao
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
sach ky » sac ky, sach ty, sach kem
thuc va » thuc vat, thuc dan, thuc day
dao vai » dao van, dao va, dao bai
va nam » van nam, ha nam, va nay
va dao » ca 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 ((sach ky) OR (sach y)) lang xa hoi. hieu va nam thuc va dao vai ((cau triet) or (cau theo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach ky) OR (sach y)) lang xa hoi. hieu va nam thuc va dao vai ((cau triet) OR (cau theo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach ky) OR (sach y)) lang xa hoi. hieu va nam thuc va dao vai ((cau triet) or (cau theo))".
• Adding a wildcard symbol may retrieve word variants: toc ((sach ky) OR (sach y)) lang xa hoi. hieu va nam thuc va dao vai ((cau triet) or (cau theo))*.