Perhaps you should try some spelling variations:
thanh dat » thanh san, thanh hai, thanh van
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
truc va » thuc va, thuc vat, trung va
dat cua » dai cua, day cua, mat cua
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
y lang » o lang, tay lang, yen lang
tuc va » thuc va, tuc xa, duc va
_ lang » o lang, _ land

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