Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, cau treo
sach tay » xach tay, sach hay, sach nay
te sach » toc sach
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, nam thuc
ca tren » cu tren, la tren, co tren
hieu va » lieu va, hieu qua
tang ma » tang van
tuc va » thuc va, truc va, tuc xa
va cam » va cham, va cac, va cao

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 tay ((tang ma) or (mang may)) hoi. hieu va cam tuc va hanh vi ((cau tren) OR (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach tay ((tang ma) OR (mang may)) hoi. hieu va cam tuc va hanh vi ((cau tren) OR (ca tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach tay ((tang ma) or (mang may)) hoi. hieu va cam tuc va hanh vi ((cau tren) OR (ca tren))".
• Adding a wildcard symbol may retrieve word variants: te sach tay ((tang ma) or (mang may)) hoi. hieu va cam tuc va hanh vi ((cau tren) OR (ca tren))*.