Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
va giao » van giao, va giai, va gia
hai cua » thai cua, dai cua, hoi cua
vai cua » dai cua, lai cua, bai cua
duc van » duc va, duc tan, duc manh
hieu va » lieu va, hieu qua
sach ly » sach y, sach lo, sach ty
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa

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 ly ((nang xa) OR (lang xa)) hoi. hieu va giao duc van hanh ((vai cua) or (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ly ((nang xa) OR (lang xa)) hoi. hieu va giao duc van hanh ((vai cua) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ly ((nang xa) OR (lang xa)) hoi. hieu va giao duc van hanh ((vai cua) or (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ly ((nang xa) OR (lang xa)) hoi. hieu va giao duc van hanh ((vai cua) or (hai cua)) tre*.