Perhaps you should try some spelling variations:
va trinh » van trinh, va tinh, lap trinh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
dang xa » dang xay, lang xa, dang va
dang ha » dong ha, dung ha, lang ha
va coc » va cuoc, va cac, va hoc
luc va » duc va, tuc va, loc va
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky ((dang xa) or (dang ha)) hoi. hieu va coc luc va trinh ((vi cua) OR (di cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((dang xa) OR (dang ha)) hoi. hieu va coc luc va trinh ((vi cua) OR (di cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((dang xa) or (dang ha)) hoi. hieu va coc luc va trinh ((vi cua) OR (di cua)) te".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((dang xa) or (dang ha)) hoi. hieu va coc luc va trinh ((vi cua) OR (di cua)) te*.