Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
trinh ve » trinh he, trinh va, trinh vi
sang ky » sang kyo, dang ky, tang ky
tang xa » trang xa, tang ma, lang xa
hieu va » lieu va, hieu qua
luc va » duc va, tuc va
ve cau » ke cau, ve cac, le cau
loc va » hoc va
ban ky » van ky, dan ky
va cau » van cau, va cac, 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 ((ban ky) or (sang ky)) tang xa hoi. hieu va cau ((loc va) OR (luc va)) trinh ve cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((ban ky) OR (sang ky)) tang xa hoi. hieu va cau ((loc va) OR (luc va)) trinh ve cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((ban ky) or (sang ky)) tang xa hoi. hieu va cau ((loc va) OR (luc va)) trinh ve cau tren".
• Adding a wildcard symbol may retrieve word variants: te ((ban ky) or (sang ky)) tang xa hoi. hieu va cau ((loc va) OR (luc va)) trinh ve cau tren*.