Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
danh sai » dung sai, danh bat, danh dau
vien cac » vien bach, vien dai, vien da
va danh » va dinh, va dan, va hanh
tu sach » thu sach, su sach, te sach
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
sai va » mai va, dai va, hai va
ve cac » va cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ky lang) or (ky dang)) xa hoi. hieu ((ve cac) OR (vien cac)) duc va danh sai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky dang)) xa hoi. hieu ((ve cac) OR (vien cac)) duc va danh sai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) or (ky dang)) xa hoi. hieu ((ve cac) OR (vien cac)) duc va danh sai va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) or (ky dang)) xa hoi. hieu ((ve cac) OR (vien cac)) duc va danh sai va triet*.