Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
dang xay » dang van, van xay
van hanh » van thanh, ban hanh, van anh
hai cua » thai cua, dai cua, hoi cua
va dinh » van dinh, va kinh, va tinh
ve giao » te giao, viet giao, van giao
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
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: thuoc sach ky ((nang x) or (dang xay)) hoi. hieu ve giao duc ((van hanh) or (va dinh)) hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky ((nang x) OR (dang xay)) hoi. hieu ve giao duc ((van hanh) OR (va dinh)) hai cua tre.
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky ((nang x) or (dang xay)) hoi. hieu ve giao duc ((van hanh) or (va dinh)) hai cua tre*.