Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
ky lang » ky nang, ky tang, tay lang
ky dang » ky nang, ky danh
duc van » duc va, duc tan, duc manh
hanh ve » hanh vi, hanh va, hanh kem
so viet » hoc viet
ve so » ve su, va so, ve co

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 lang) OR (ky dang)) xa hoi. hieu ((te tai) or (va cac)) duc van hanh ve so viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky lang) OR (ky dang)) xa hoi. hieu ((te tai) OR (va cac)) duc van hanh ve so viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky lang) OR (ky dang)) xa hoi. hieu ((te tai) or (va cac)) duc van hanh ve so viet".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky lang) OR (ky dang)) xa hoi. hieu ((te tai) or (va cac)) duc van hanh ve so viet*.