Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
dua tren » dung tren
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
dang van » hoang van, hang va
sach ky » sac ky, sach y, sach ty
vu sach » vu bach, su sach, vu khach
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky ((lang xa) or (dang van)) hoi. hieu va nam thuc dan hanh vi ((dua tren) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((lang xa) OR (dang van)) hoi. hieu va nam thuc dan hanh vi ((dua tren) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((lang xa) or (dang van)) hoi. hieu va nam thuc dan hanh vi ((dua tren) or (cua triet))*.