Perhaps you should try some spelling variations:
cau tren » dau tren, ca tren, cau treo
te sach » toc sach
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
cu tren » tu tren, dua tren
nang xa » lang xa, nang ma, mang xa
dam tu » nam tu, cam tu, tam tu
va dam » van dam, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y ((nang xa) or (nang x)) hoi. hieu va dam tu va hanh di ((cau tren) OR (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y ((nang xa) OR (nang x)) hoi. hieu va dam tu va hanh di ((cau tren) OR (cu tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y ((nang xa) or (nang x)) hoi. hieu va dam tu va hanh di ((cau tren) OR (cu tren))".
• Adding a wildcard symbol may retrieve word variants: te sach y ((nang xa) or (nang x)) hoi. hieu va dam tu va hanh di ((cau tren) OR (cu tren))*.