Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
vat thanh » dat thanh, gat thanh, tat thanh
thanh ve » hanh ve, thanh va, thanh vien
te sach » toc sach
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
ve cac » va cac, vien cac
ve cua » le cua, de cua, te cua
ve cau » ke cau, va cau, le cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (thuoc sach)) ky nang ma hoa. hieu ((ve cau) or (ve cac)) thuc vat thanh ve cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (thuoc sach)) ky nang ma hoa. hieu ((ve cau) OR (ve cac)) thuc vat thanh ve cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (thuoc sach)) ky nang ma hoa. hieu ((ve cau) or (ve cac)) thuc vat thanh ve cua tre*.