Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
cua viet » hoa viet, cua vat, cua dieu
tu sach » thu sach, te sach, tu cach
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
ca viet » va viet, co viet, hoa viet
hieu ve » hieu va, hieu van
su sach » so sach, vu sach
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho

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) OR (su sach)) ky nang x hoi. hieu ve cac duc van thanh san ((cua viet) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang x hoi. hieu ve cac duc van thanh san ((cua viet) OR (ca viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) ky nang x hoi. hieu ve cac duc van thanh san ((cua viet) or (ca viet))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) ky nang x hoi. hieu ve cac duc van thanh san ((cua viet) or (ca viet))*.