Perhaps you should try some spelling variations:
thanh duc » thach duc, than duc, thinh duc
van thanh » ban thanh, van tuan
van hanh » ban hanh, van anh, van ban
cua viet » hoa viet, cua vat, cua dieu
va thanh » gia thanh, ban thanh, va tinh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
ca viet » va viet, co viet, hoa viet

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