Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
kho tang » cao tang
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, tu cach
tang xa » trang xa, tang ma, lang xa
te sach » toc sach
van cau » van dau, van hau, van chat
tuc va » truc va, tuc xa, duc va
va cau » va cac, va dau, va cao

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)) kho tang xa hoi. hieu van cau ((tuc va) OR (thuc va)) hang va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) kho tang xa hoi. hieu van cau ((tuc va) OR (thuc va)) hang va cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) kho tang xa hoi. hieu van cau ((tuc va) OR (thuc va)) hang va cau tren*".