Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
thuc va » thuc vat, thuc dan, thuc day
su cham » su pham, tu cham, vu cham
sach ky » sac ky, sach y, sach ty
hieu su » hieu sau, tieu su, hieu so
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet
ma hoi » xa hoi, ma hoa, me hoi
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua

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 sang ((ma hoi) OR (mai hoi)). hieu su cham ((thuc va) or (tuc xa)) dan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang ((ma hoi) OR (mai hoi)). hieu su cham ((thuc va) OR (tuc xa)) dan vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky sang ((ma hoi) OR (mai hoi)). hieu su cham ((thuc va) or (tuc xa)) dan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky sang ((ma hoi) OR (mai hoi)). hieu su cham ((thuc va) or (tuc xa)) dan vi cua tre*.