Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
te sach » toc sach
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
tu nong » tu dong, tu cong, tu tong
tu nang » tru nang, tu nano, tu lang
tuc va » truc va, tuc xa, duc va
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 ((tu nang) OR (tu nong)) xa hoi. hieu va co ((tuc va) or (thuc va)) thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((tu nang) OR (tu nong)) xa hoi. hieu va co ((tuc va) OR (thuc va)) thanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((tu nang) OR (tu nong)) xa hoi. hieu va co ((tuc va) or (thuc va)) thanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ((tu nang) OR (tu nong)) xa hoi. hieu va co ((tuc va) or (thuc va)) thanh dai cua tre*.