Perhaps you should try some spelling variations:
su sach » so sach, vu sach
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cac toc » cac toi, cac nuoc, cac thoi
cac tac » cac bac, cac dac, cac tai
va tran » va trang, va trac, ha tran
thi cua » thai cua, thi cuc, tri cua
cua tre » cua te, cuu tre, cua triet
y lang » o lang, _ lang, tay lang

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y lang xa hoi. hieu va ((cac toc) or (cac tac)) va tran thi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y lang xa hoi. hieu va ((cac toc) OR (cac tac)) va tran thi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach y lang xa hoi. hieu va ((cac toc) or (cac tac)) va tran thi cua tre*.