Perhaps you should try some spelling variations:
va trinh » van trinh, va tinh, lap trinh
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
cao hoi » co hoi, cao hoc, tao hoi
cam duc » cam xuc, cao duc, pham duc
va cam » va cham, va cac, va cao
vi su » ve su, ki su, oi su

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky nang ((cao hoi) or (cau hoi)). lieu va cam duc va trinh ((vi su) OR (va su)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang ((cao hoi) OR (cau hoi)). lieu va cam duc va trinh ((vi su) OR (va su)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang ((cao hoi) or (cau hoi)). lieu va cam duc va trinh ((vi su) OR (va su)) viet".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang ((cao hoi) or (cau hoi)). lieu va cam duc va trinh ((vi su) OR (va su)) viet*.