Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cao duc » dao duc, cao suc, giao duc
va hanh » van hanh, va thanh, va danh
hanh co » anh co, danh co, hanh mo
cua tre » cua te, cuu tre, cua triet
va cao » va cac, va co, va dao
co cua » con cua, ca cua, cong 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 hoach)) ky ((nang xa) OR (lang xa)) hoi. hieu va cao duc va hanh co cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky ((nang xa) OR (lang xa)) hoi. hieu va cao duc va hanh co cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu hoach)) ky ((nang xa) OR (lang xa)) hoi. hieu va cao duc va hanh co cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky ((nang xa) OR (lang xa)) hoi. hieu va cao duc va hanh co cua tre*.