Perhaps you should try some spelling variations:
thien van » thi van
tu sach » thu sach, su sach, te sach
nang xa » lang xa, nang ma, mang xa
hieu va » lieu va, hieu qua
thue va » thuc va, thuyet va, thuc vat
va hanh » van hanh, va thanh, va danh
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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 y ((nang xa) OR (nang x)) hoi. ((hieu va) or (thien van)) luat thue va hanh vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (nang x)) hoi. ((hieu va) OR (thien van)) luat thue va hanh vi cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang xa) OR (nang x)) hoi. ((hieu va) or (thien van)) luat thue va hanh vi cua tu".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) OR (nang x)) hoi. ((hieu va) or (thien van)) luat thue va hanh vi cua tu*.