Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
cac toc » cac toi, cac nuoc, cac thoi
dan thi » dang thi, tran thi, dinh thi
cuu tre » cua tre, cau tren, cau treo
toc va » hoc va, toc ta, tuc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty ((nang x) or (nang ma)) hoi. lieu va cac toc va ((dan thi) or (cau thi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((nang x) OR (nang ma)) hoi. lieu va cac toc va ((dan thi) OR (cau thi)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: so sach ty ((nang x) or (nang ma)) hoi. lieu va cac toc va ((dan thi) or (cau thi)) cuu tre*.