Perhaps you should try some spelling variations:
van thanh » ban thanh
thanh duc » thach duc, than duc, thinh duc
va thanh » gia thanh, ban thanh, va tinh
van tuan » van quan, van ban, anh tuan
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
vai cua » hai cua, lai cua, bai cua

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 thanh) or (van tuan)) ((vai cua) OR (dai cua)) 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 thanh) OR (van tuan)) ((vai cua) OR (dai cua)) 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 thanh) or (van tuan)) ((vai cua) OR (dai cua)) viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu va thanh duc ((van thanh) or (van tuan)) ((vai cua) OR (dai cua)) viet*.