Perhaps you should try some spelling variations:
va trinh » van trinh, va tinh, lap trinh
trinh ve » trinh he, trinh va, trinh vi
cau tren » cu tren, dau tren, ca tren
dang ky » dang y, dan ky, dong ky
tang xa » trang xa, tang ma, lang xa
hieu va » lieu va, hieu qua
cau loc » hau loc, cau hoc, cau luc
ban ky » van ky, dan ky
va cau » van cau, va cac, va dau
loc va » hoc va, luc va
ve cau » ke cau, ve cac, le cau

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 (dang ky)) tang xa hoi. hieu va cau loc va trinh ve cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((ban ky) OR (dang ky)) tang xa hoi. hieu va cau loc va trinh ve cau tren.
• Adding a wildcard symbol may retrieve word variants: te ((ban ky) or (dang ky)) tang xa hoi. hieu va cau loc va trinh ve cau tren*.