Perhaps you should try some spelling variations:
thien van » thi van
van thoai » van hoai, van thai, than thoai
bo sach » co sach, hoc sach
cua tre » cua te, cuu tre, cua triet
ca tren » cau tren, cu tren, la tren
sach lo » sach dao, sach doi, sach hoi
nang xa » nang x, lang xa, nang ma
lo nang » ho nang, ly nang, loai nang
tuc va » thuc va, truc va, duc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach lo nang xa hoi. thien van thoai ((tuc va) OR (tuc xa)) hanh vi ((cua tre) or (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach lo nang xa hoi. thien van thoai ((tuc va) OR (tuc xa)) hanh vi ((cua tre) OR (ca tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "bo sach lo nang xa hoi. thien van thoai ((tuc va) OR (tuc xa)) hanh vi ((cua tre) or (ca tren))".
• Adding a wildcard symbol may retrieve word variants: bo sach lo nang xa hoi. thien van thoai ((tuc va) OR (tuc xa)) hanh vi ((cua tre) or (ca tren))*.