Perhaps you should try some spelling variations:
dung doi » huong doi, dung tai, dung co
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
van cac » van cau, van bac, dan cac
van hac » van hoc, van ha, van hai
truc va » thuc va, thuc vat, trung va
va dung » van dung, va duong, vat dung
doi 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: tu sach ky nang xa hoi. hieu ((van cac) or (van hac)) truc va dung doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu ((van cac) OR (van hac)) truc va dung doi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu ((van cac) or (van hac)) truc va dung doi cua tre*.