Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
toc sach » hoc sach, doc sach, thuoc sach
thuc dan » thuc hanh, hoc dan, thuc vat
vai cua » dai cua, hai cua, lai cua
thuc va » thuc vat, thuc day
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
tu lang » cu lang, tu lanh, xu lang
va co » vo co

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 (toc sach)) tu lang xa hoi. hieu va co ((thuc va) OR (thuc dan)) thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) tu lang xa hoi. hieu va co ((thuc va) OR (thuc dan)) thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) tu lang xa hoi. hieu va co ((thuc va) OR (thuc dan)) thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) tu lang xa hoi. hieu va co ((thuc va) OR (thuc dan)) thanh vai cua tre*.