Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
ky dang » ky danh
hieu va » lieu va, hieu qua
cac tuc » cac tu, cac tac, cac nuoc
cac toc » cac toi, cac nuoc, cac thoi
dan vai » dan va, dan tai, dan vat
ca viet » va viet, co viet, hoa viet
va dan » ca dan, va dao, va dau
vai ca » vai cac, vai cua, bai ca

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

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