Perhaps you should try some spelling variations:
cua triet » su triet, va triet
cong xay » thong xay, trong xay, cong ty
hieu van » hieu va, thien van, lieu va
cua viet » ca viet, hoa viet, cua vat
su sach » so sach, vu sach
sach ly » sach y, sach lo, sach ty
von xay » van xay, mong xay, vien xay
nam xuc » cam xuc, nam xua, nam thuc
xuc va » duc va, tuc va, luc va
do hai » do thai, doc hai, do dai
va do » va dao, va doc, va co

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ly ((von xay) OR (cong xay)) hoi. hieu van nam xuc va do hai ((cua triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly ((von xay) OR (cong xay)) hoi. hieu van nam xuc va do hai ((cua triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly ((von xay) OR (cong xay)) hoi. hieu van nam xuc va do hai ((cua triet) or (cua viet))".
• Adding a wildcard symbol may retrieve word variants: su sach ly ((von xay) OR (cong xay)) hoi. hieu van nam xuc va do hai ((cua triet) or (cua viet))*.