Perhaps you should try some spelling variations:
thuat sai » thuat bai, thuat san, thuat cai
khoa viet » khoan viet, hoa viet, thoai viet
voi khoa » noi khoa, hoi khoa, loi khoa
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
sai ky » sac ky
va nam » ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sai ky lang xa hoi. hieu ((va nam) or (van nam)) truoc ((va hanh) OR (va danh)) voi khoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sai ky lang xa hoi. hieu ((va nam) OR (van nam)) truoc ((va hanh) OR (va danh)) voi khoa viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sai ky lang xa hoi. hieu ((va nam) or (van nam)) truoc ((va hanh) OR (va danh)) voi khoa viet".
• Adding a wildcard symbol may retrieve word variants: thuat sai ky lang xa hoi. hieu ((va nam) or (van nam)) truoc ((va hanh) OR (va danh)) voi khoa viet*.