Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
dai cuu » dai cua, dai huu
va danh » va dinh, va dan, va hanh
hai duc » hoai duc, mai duc, ha duc
qua hai » qua hoat
sach ky » sac ky, sach y, sach ty
lang ha » long ha
lang xa » dang xay, lang van
cuu tre » cua tre, cau tren, cau treo

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 ky ((lang xa) or (lang ha)) hoi. hieu qua hai duc ((van hanh) or (va danh)) dai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((lang xa) OR (lang ha)) hoi. hieu qua hai duc ((van hanh) OR (va danh)) dai cuu tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((lang xa) or (lang ha)) hoi. hieu qua hai duc ((van hanh) or (va danh)) dai cuu tre*.