Perhaps you should try some spelling variations:
thac toc » cac toc, thac cac, thi toc
hieu va » lieu va, hieu qua
va thac » van thac, va thuc, va tac
sach ty » sach y, sach tu, sach thu
danh vi » hanh vi, dinh vi, danh di
danh du » danh dau, danh tu, dinh du
cuu tre » cua tre, cau tren, cau treo
sac ky » cac ky, sai ky
toc va » hoc va, toc ta, tuc va
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ty) or (sac ky)) nang x hoi. hieu va thac toc va ((danh vi) or (danh du)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ty) OR (sac ky)) nang x hoi. hieu va thac toc va ((danh vi) OR (danh du)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: thu ((sach ty) or (sac ky)) nang x hoi. hieu va thac toc va ((danh vi) or (danh du)) cuu tre*.