Perhaps you should try some spelling variations:
dung tren » dung trong, dung trung
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
cuu tre » cua tre, cau tren, cau treo
nam tu » nam thu, nam thuc
tu van » tu va

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 xa) or (lang xa)) hoi. hieu van nam tu van hanh vi ((dung tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky ((nang xa) OR (lang xa)) hoi. hieu van nam tu van hanh vi ((dung tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: hoc sach ky ((nang xa) or (lang xa)) hoi. hieu van nam tu van hanh vi ((dung tren) or (cuu tre))*.