Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
trang xa » trang va, trang ha, trong xa
va trinh » van trinh, va tinh, lap trinh
tang xa » tang ma, lang xa, tang ha
hieu va » lieu va, hieu qua
cam luc » cam xuc, cau luc
ve cac » va cac
tu ban » thu ban, te ban
luc va » duc va, tuc va, loc va
ban ky » van ky, dan ky
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: tu ban ky ((tang xa) OR (trang xa)) hoi. hieu va cam luc va trinh ((ve cac) or (vien cac)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ban ky ((tang xa) OR (trang xa)) hoi. hieu va cam luc va trinh ((ve cac) OR (vien cac)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ban ky ((tang xa) OR (trang xa)) hoi. hieu va cam luc va trinh ((ve cac) or (vien cac)) tren".
• Adding a wildcard symbol may retrieve word variants: tu ban ky ((tang xa) OR (trang xa)) hoi. hieu va cam luc va trinh ((ve cac) or (vien cac)) tren*.