Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
sach thi » sach thu, sach tai, sach thieu
thi hanh » thi thanh
hieu van » hieu va, thien van, lieu va
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
hanh xa » hanh va, hanh ma, hanh xu
hieu ve » hieu va
hai cua » thai cua, dai cua, hoi 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 thi hanh xa hoi. ((hieu ve) or (hieu van)) am thuc ((van ban) or (van thanh)) hai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thi hanh xa hoi. ((hieu ve) OR (hieu van)) am thuc ((van ban) OR (van thanh)) hai cua viet.
• Adding a wildcard symbol may retrieve word variants: tu sach thi hanh xa hoi. ((hieu ve) or (hieu van)) am thuc ((van ban) or (van thanh)) hai cua viet*.