Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
va giao » van giao, va giai, va gia
va danh » va dinh, va dan, va hanh
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ky ((nang x) or (lang xa)) hoi. hieu va giao duc ((van hanh) or (va danh)) hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky ((nang x) OR (lang xa)) hoi. hieu va giao duc ((van hanh) OR (va danh)) hai cua tre.
• Adding a wildcard symbol may retrieve word variants: hoc sach ky ((nang x) or (lang xa)) hoi. hieu va giao duc ((van hanh) or (va danh)) hai cua tre*.