Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
than luc » nhan luc, than duc, thanh luu
tham luc » tham nuoc, tham thuc, nhan luc
hieu va » lieu va, hieu qua
tu sach » thu sach, su sach, te sach
o lang » hoa lang, hoi lang
y lang » _ lang, tay lang, yen lang
ca dan » cac dan, ca dao
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 ((y lang) or (o lang)) xa hoi. hieu va ((tham luc) OR (than luc)) ca dan ca cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y lang) OR (o lang)) xa hoi. hieu va ((tham luc) OR (than luc)) ca dan ca cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y lang) or (o lang)) xa hoi. hieu va ((tham luc) OR (than luc)) ca dan ca cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y lang) or (o lang)) xa hoi. hieu va ((tham luc) OR (than luc)) ca dan ca cua viet*.