Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
sang kyo » sang tao, dang ky, sang cho
duc manh » suc manh, duc anh, duc minh
cua viet » ca viet, hoa viet, cua vat
sang ky » dang ky, tang ky, bang ky
lang xa » lang ha, dang xay, lang van
duc van » duc va, duc tan, duc phan
qua ca » qua cac, qua cua, qua cai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sang ky) or (sang kyo)) lang xa hoi. hieu qua ca ((duc van) OR (duc manh)) thanh dai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sang ky) OR (sang kyo)) lang xa hoi. hieu qua ca ((duc van) OR (duc manh)) thanh dai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sang ky) or (sang kyo)) lang xa hoi. hieu qua ca ((duc van) OR (duc manh)) thanh dai cua viet".
• Adding a wildcard symbol may retrieve word variants: tu ((sang ky) or (sang kyo)) lang xa hoi. hieu qua ca ((duc van) OR (duc manh)) thanh dai cua viet*.