Perhaps you should try some spelling variations:
thanh lap » thanh san, phan lap, thanh hai
hieu van » hieu va, thien van, lieu va
cua viet » ca viet, cua vat, cua dieu
thu sach » thuat sach, thuoc sach, thu hoach
va thanh » gia thanh, ban thanh, va tinh
cac duc » cac du, cao duc, cac dac
tu sach » su sach, te sach, tu cach
van cac » van hac, van cau, van bac
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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)) ky nang o hai. hieu van cac duc va thanh lap ((cua viet) OR (hoa viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang o hai. hieu van cac duc va thanh lap ((cua viet) OR (hoa viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang o hai. hieu van cac duc va thanh lap ((cua viet) OR (hoa viet))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang o hai. hieu van cac duc va thanh lap ((cua viet) OR (hoa viet))*.