Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
cua viet » ca viet, hoa viet, cua vat
tu sach » su sach, te sach, tu cach
qua cac » cua cac
cac duc » cac du, cao duc, cac dac
y nang » ly nang, v nang, may nang
va dan » ca dan, va dao, va dau
ca cua » co 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) or (thu sach)) ((y nang) OR (ky nang)) xa hoi. hieu qua cac duc va dan ca cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ((y nang) OR (ky nang)) xa hoi. hieu qua cac duc va dan ca cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ((y nang) OR (ky nang)) xa hoi. hieu qua cac duc va dan ca cua viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ((y nang) OR (ky nang)) xa hoi. hieu qua cac duc va dan ca cua viet*.