Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
va hanh » va thanh, va danh, ban hanh
lam cua » nam cua, lam chat
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao

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 ((nang x) or (lang xa)) hoi. hieu va cam duc ((va hanh) OR (van hanh)) lam cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang x) OR (lang xa)) hoi. hieu va cam duc ((va hanh) OR (van hanh)) lam cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang x) or (lang xa)) hoi. hieu va cam duc ((va hanh) OR (van hanh)) lam cua tre*".