Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
cac tuc » cac toc, cac tu, cac tac
dau thi » cau thi, dao thi, dam thi
dan thi » dang thi, tran thi, dinh thi
cuu tre » cua tre, cau tren, cau treo
tuc va » thuc va, truc va, tuc xa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang x) OR (nang ma)) hoi. lieu va cac tuc va ((dau thi) OR (dan thi)) cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang x) or (nang ma)) hoi. lieu va cac tuc va ((dau thi) OR (dan thi)) cuu tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang x) or (nang ma)) hoi. lieu va cac tuc va ((dau thi) OR (dan thi)) cuu tre*.