Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
dang xay » dang van, van xay
thu sach » thuat sach, thuoc sach, thu hoach
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
hai tuc » thai tuc, hai cuc, thai thuc
hieu va » lieu va, hieu qua
tu sach » su sach, te sach, tu cach
nang xa » nang x, lang xa, nang ma
va hai » van hai, va chai, va khai
tuc va » thuc va, truc va, tuc xa

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) OR (thu sach)) y ((nang xa) or (dang xay)) hoi. hieu va hai tuc va hanh va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) y ((nang xa) OR (dang xay)) hoi. hieu va hai tuc va hanh va su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) y ((nang xa) or (dang xay)) hoi. hieu va hai tuc va hanh va su triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) y ((nang xa) or (dang xay)) hoi. hieu va hai tuc va hanh va su triet*.