Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
thanh dat » thanh san, thanh hai, thanh van
nang van » dang van, tang van, lang van
nam thuc » nam thuoc, am thuc, nam thu
tu sach » thu sach, su sach, tu cach
te sach » toc sach
van hoc » van hoa
qua nam » quan nam, cua nam, quang nam
dat cua » dai cua, day cua, mat cua
cua tre » cua te, cuu tre, cua triet

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) or (te sach)) ky nang van hoc. hieu qua nam thuc vat thanh dat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky nang van hoc. hieu qua nam thuc vat thanh dat cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky nang van hoc. hieu qua nam thuc vat thanh dat cua tre*.